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Fencer Vulns
high 7.5

CVE-2026-39820 json

Quadratic string concatentation in consumeComment in net/mail

published 2026-05-07 6 mo ago modified 2026-10-26 14 d ago also BIT-golang-2026-39820 , EUVD-2026-28423 , GO-2026-4986

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations.

Patch / fix

  • bitnami golang 1.25.10, 1.26.3
  • go stdlib 1.25.10, 1.26.3
  • Go standard library net/mail 1.25.10, 1.26.3
  • Red Hat Red Hat Ansible Automation Platform 2.5 for RHEL 8 0:2.5.10-7.el8ap
  • Red Hat Red Hat Ansible Automation Platform 2.5 for RHEL 9 0:2.6.17-2.el9ap
  • Red Hat Red Hat Ansible Automation Platform 2.6 for RHEL 9 0:2.6.17-2.el9ap
  • Red Hat Red Hat Enterprise Linux 10 0:0.152.1-2.el10_2, 0:1.26.3-4.el10_2, 0:10.2.6-28.el10_2.5, 0:52.1-1.el10_2.2, 0:165.1-3.el10_2.2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:0.152.1-2.el10_0, 0:1.26.5-1.el10_0, 0:2.21.0-3.el10_0.4, 0:10.2.6-26.el10_0, 0:134.1-12.el10_0
  • Red Hat Red Hat Enterprise Linux 8 0:9.2.10-33.el8_10, 0:101.5-2.el8_10, 8100020260518131104.a3795dee
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:75-10.el8_8
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:75-10.el8_8
  • Red Hat Red Hat Enterprise Linux 9 0:0.152.1-2.el9_8, 0:1.26.3-1.el9_8, 0:10.2.6-23.el9_8.3, 0:52.1-1.el9_8.2, 0:165.1-4.el9_8.1
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:1.26.5-1.el9_2, 0:76.1-9.el9_2
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:0.152.1-2.el9_4, 0:1.26.5-1.el9_4, 0:101.3-4.el9_4.6
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:0.152.1-2.el9_6, 0:1.26.5-1.el9_6, 0:2.21.0-7.el9_6.1, 0:10.2.6-22.el9_6, 0:132.2-12.el9_6
  • Red Hat Red Hat OpenShift Container Platform 4.12 0:1.25.5-34.rhaos4.12.git6120b13.el8, 0:4.12.0-202608131627.p2.g0e18cfc.assembly.stream.el8, 1786752886
  • Red Hat Red Hat OpenShift Container Platform 4.13 0:1.26.5-32.rhaos4.13.git1088e36.el8, 0:4.13.0-202608122150.p2.gbbc7c0c.assembly.stream.el8
  • Red Hat Red Hat OpenShift Container Platform 4.16 0:1.29.13-12.rhaos4.16.git979a5e6.el8, 0:4.16.0-202608111505.p2.g6f88b58.assembly.stream.el8, 0:4.16.0-202608111505.p2.g26b43df.assembly.stream.el8, 0:4.16.0-202608111505.p2.g41c4e9b.assembly.stream.el8, 0:4.16.0-202608111505.p2.ga3ebdc0.assembly.stream.el8, 0:4.16.0-202608111505.p2.ga53e9de.assembly.stream.el8, 0:4.16.69-202608202336.p0.g763478c.assembly.4.16.69.el9, 1786788280
  • Red Hat Red Hat OpenShift Container Platform 4.17 0:1.30.14-11.rhaos4.17.git1e2a16d.el8, 0:4.17.0-202608122146.p2.g5bcfbfd.assembly.stream.el8, 0:4.17.0-202608122146.p2.g8ce997d.assembly.stream.el8, 0:4.17.0-202608122146.p2.g144bace.assembly.stream.el8, 0:4.17.0-202608132055.p2.g4e295fa.assembly.stream.el8, 0:4.17.0-202608201812.p2.g7189593.assembly.stream.el8, 1787549445
  • Red Hat Red Hat OpenShift Container Platform 4.18 0:1.31.13-11.rhaos4.18.git817a650.el9, 0:4.18.0-202608121933.p2.g6ea2356.assembly.stream.el8, 0:4.18.0-202608121933.p2.g9795abd.assembly.stream.el8, 0:4.18.0-202608121933.p2.gc395190.assembly.stream.el8, 0:4.18.0-202608132034.p2.g6febe61.assembly.stream.el8, 0:4.18.0-202608132034.p2.g91c2408.assembly.stream.el8, 0:4.18.54-202608211117.p0.g8eb6c29.assembly.4.18.54.el9, 1786754308
  • Red Hat Red Hat OpenShift Container Platform 4.19 0:1.32.13-9.rhaos4.19.git2100f27.el9, 0:3.31.0-5.rhaos4.19.el9, 0:4.19.0-202608111604.p2.g63adf01.assembly.stream.el9, 0:4.19.0-202608111604.p2.g425c1c5.assembly.stream.el9, 0:4.19.0-202608111604.p2.gb2a93a6.assembly.stream.el8, 0:4.19.43-202608141837.p0.gcd3decf.assembly.4.19.43.el9, 1786489910
  • Red Hat RHEM 1.1 for RHEL 10 0:1.1.4-1.el10em
  • Red Hat RHEM 1.1 for RHEL 9 0:1.1.4-1.el9em
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.19 1786613805
  • Red Hat Logging for Red Hat OpenShift 6 1785419067
  • Red Hat Logging for Red Hat OpenShift 6.2 1784748010
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.4 1782405469
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.5 1786645248
  • Red Hat multicluster engine for Kubernetes 2.11 1786912006
  • Red Hat OpenShift API for Data Protection 1.3 1785177357
  • golang-1.26 Debian 14 1.26.3-1

debian advisories DEBIAN-CVE-2026-39820

  • cri-o openshift 4.19 1.32.13-14.rhaos4.19.git3c1400a.el9
  • openshift openshift 4.19 4.19.0-202609141900.p2.g63adf01.assembly.stream.el9
  • openshift-clients openshift 4.19 4.19.0-202609141900.p2.ga2c805b.assembly.stream.el8
  • openshift-clients openshift 4.19 4.19.0-202609141900.p2.ga2c805b.assembly.stream.el9
  • openshift-kubelet openshift 4.19 4.19.0-202609141900.p2.g63adf01.assembly.stream.el9
  • openshift-hyperkube openshift 4.19 4.19.0-202609141900.p2.g63adf01.assembly.stream.el9
  • openshift-kube-apiserver openshift 4.19 4.19.0-202609141900.p2.g63adf01.assembly.stream.el9
  • openshift-kube-scheduler openshift 4.19 4.19.0-202609141900.p2.g63adf01.assembly.stream.el9

red hat advisories RHSA-2026:76795RHSA-2026:76809RHSA-2026:68534RHSA-2026:68527RHSA-2026:65838RHSA-2026:68504

  • go1.25-openssl SLES for SAP applications 16.0, SLES 16.0 1.25.12-160000.1.1
  • go1.26-openssl SLES for SAP applications 16.0, SLES 16.0 1.26.4-160000.1.1

suse advisories SUSE-SU-2026:22638-1SUSE-SU-2026:22572-1

  • percona-toolkit openSUSE Tumbleweed 3.7.1.4-1.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • go1.25-openssl openSUSE Leap 16.0 1.25.12-160000.1.1
  • go1.26-openssl openSUSE Leap 16.0 1.26.4-160000.1.1
  • go1.26 openSUSE Tumbleweed 1.26.3-1.1
  • go1.25 openSUSE Tumbleweed 1.25.10-1.1

opensuse advisories openSUSE-SU-2026:12166-1openSUSE-SU-2026:21483-1openSUSE-SU-2026:21319-1openSUSE-SU-2026:21254-1openSUSE-SU-2026:10741-1openSUSE-SU-2026:10723-1

  • osbuild-composer AlmaLinux 8 101.5-2.el8_10.alma.1
  • osbuild-composer-core AlmaLinux 8 101.5-2.el8_10.alma.1
  • osbuild-composer-worker AlmaLinux 8 101.5-2.el8_10.alma.1
  • opentelemetry-collector AlmaLinux 10 0.152.1-2.el10_2
  • opentelemetry-collector AlmaLinux 9 0.152.1-2.el9_8
  • osbuild-composer AlmaLinux 9 165.1-4.el9_8.1.alma.1
  • osbuild-composer-core AlmaLinux 9 165.1-4.el9_8.1.alma.1
  • osbuild-composer-worker AlmaLinux 9 165.1-4.el9_8.1.alma.1

almalinux advisories ALSA-2026:66016ALSA-2026:65116ALSA-2026:65117ALSA-2026:65153ALSA-2026:63022ALSA-2026:62406

  • osbuild-composer Rocky Linux 8 101.5-2.el8_10.rocky.0.6
  • osbuild-composer Rocky Linux 10 165.1-3.el10_2.2.rocky.0.1
  • image-builder Rocky Linux 9 52.1-1.el9_8.2
  • image-builder Rocky Linux 10 52.1-1.el10_2.2.rocky.0.1
  • opentelemetry-collector Rocky Linux 10 0.152.1-2.el10_2
  • opentelemetry-collector Rocky Linux 9 0.152.1-2.el9_8
  • osbuild-composer Rocky Linux 9 165.1-4.el9_8.1.rocky.0.1
  • grafana Rocky Linux 10 10.2.6-28.el10_2.5

rocky linux advisories RLSA-2026:66016RLSA-2026:65895RLSA-2026:65886RLSA-2026:65534RLSA-2026:65116RLSA-2026:65117

  • go Alpine 3.23 1.25.10-r0
  • go Alpine 3.24 1.26.3-r0
  • rclone Alpine 3.24 1.74.1-r0

alpine advisories ALPINE-CVE-2026-39820

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-39820 updated cvss 7.5

net/mail: golang: Go net/mail: Denial of Service via crafted email inputs

  • Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 rhai/assisted-installer-rhel9
    affected: workaround, no fix available
  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9-operator, openshift-sandboxed-containers/osc-monitor-rhel9, confidential-compute-attestation-tech-preview/trustee-rhel9-operator Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat ExternalDNS Operator edo/external-dns-rhel9, edo/external-dns-rhel9-operator Red Hat Fence Agents Remediation Operator redhat-user-workloads/rhwa-tenant/fence-agents-remediation/far-operator-0-8 Red Hat File Integrity Operator compliance/openshift-file-integrity-rhel8-operator
    affected: workaround, no fix available
  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/cluster-logging-rhel9-operator Red Hat Logical Volume Manager Storage lvms4/topolvm-rhel8
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Machine Deletion Remediation Operator redhat-user-workloads/rhwa-tenant/machine-deletion-remediation/mdr-operator-0-7 Red Hat Multiarch Tuning Operator multiarch-tuning/multiarch-tuning-rhel9-operator Red Hat Multicluster Engine for Kubernetes multicluster-engine/work-rhel9, multicluster-engine/maestro-rhel9, multicluster-engine/placement-rhel9, multicluster-engine/addon-manager-rhel9, multicluster-engine/assisted-installer-rhel8, multicluster-engine/assisted-installer-rhel9, +6 more
    affected: workaround, no fix available
  • Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-agent-rhel8
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Node HealthCheck Operator redhat-user-workloads/rhwa-tenant/node-healthcheck-operator/nhc-operator-0-12 Red Hat Node Maintenance Operator redhat-user-workloads/rhwa-tenant/node-maintenance-operator/nmo-operator-5-7 Red Hat OpenShift Developer Tools and Services helm Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-rhel9-operator Red Hat OpenShift Pipelines openshift-pipelines-client Red Hat OpenShift Serverless kn-workflow-plugin
    +4 more products
    Red Hat OpenShift Service Mesh 2 openshift-service-mesh/pilot-rhel8 Red Hat OpenShift Service Mesh 3 ossm-2/openshift-golang-builder-container Red Hat Power monitoring for Red Hat OpenShift openshift-power-monitoring/power-monitoring-rhel9-operator Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/klusterlet-addon-controller-rhel9
    affected: workaround, no fix available
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 6 rhceph/rhceph-6-dashboard-rhel9 Red Hat Ceph Storage 9 rhceph/alloy-rhel10
    affected: workaround, no fix available “Fix deferred”
show 3 more
  • Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-preflight
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 9 ignition, ignition-edge, ignition-grub, gvisor-tap-vsock, ignition-validate, rhel9/bootc-image-builder, +2 more Red Hat Enterprise Linux 10 ignition, gvisor-tap-vsock, rhel10/bootc-image-builder, rhel10-eus/rhel-10.0-bootc-image-builder
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 golang Red Hat OpenShift AI (RHOAI) rhoai/odh-maas-api-rhel9, rhoai/odh-ml-pipelines-driver-rhel9, rhoai/odh-ml-pipelines-launcher-rhel9, rhoai/odh-ml-pipelines-api-server-v2-rhel9, rhoai/odh-modelmesh-serving-controller-rhel9, rhoai/odh-ai-gateway-payload-processing-rhel9, +4 more Red Hat OpenShift Cluster Manager CLI ocm-cli-clients/ocm-cli-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-node, openshift4/ose-sdn-rhel7, openshift4/ose-kube-rbac-proxy-rhel9, ossm-2/openshift-golang-builder-container Red Hat OpenShift Container Platform 5 openshift5/ose-kube-rbac-proxy-rhel9 Red Hat Openshift Data Foundation 4 odf4/odf-cli-rhel9
    +6 more products
    Red Hat OpenShift Dev Workspaces Operator devworkspace/devworkspace-rhel9-operator Red Hat OpenShift distributed tracing 3 rhosdt/tempo-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9 Red Hat OpenShift Virtualization 4 kubevirt, ossm-2/openshift-golang-builder-container Red Hat Quay 3 quay/quay-builder-rhel8, quay/quay-builder-rhel9 Red Hat Trusted Artifact Signer rhtas/ec-rhel9
    affected: workaround, no fix available

4 more affected, 78 more fixed, 85 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami golang
<1.25.10
>=1.26.0-0, <1.26.3
1.25.10
1.26.3
go stdlib
<1.25.10
>=1.26.0-0, <1.26.3
1.25.10
1.26.3

Affected products

  • Go standard library net/mail
  • Red Hat Red Hat Ansible Automation Platform 2.5 for RHEL 8
  • Red Hat Red Hat Ansible Automation Platform 2.5 for RHEL 9
  • Red Hat Red Hat Ansible Automation Platform 2.6 for RHEL 9
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat OpenShift Container Platform 4.12
  • Red Hat Red Hat OpenShift Container Platform 4.13
  • Red Hat Red Hat OpenShift Container Platform 4.16
  • Red Hat Red Hat OpenShift Container Platform 4.17
  • Red Hat Red Hat OpenShift Container Platform 4.18
  • Red Hat Red Hat OpenShift Container Platform 4.19
  • Red Hat RHEM 1.1 for RHEL 10
  • Red Hat RHEM 1.1 for RHEL 9
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.19
  • Red Hat Logging for Red Hat OpenShift 6
  • Red Hat Logging for Red Hat OpenShift 6.2
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.4
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.5
  • Red Hat multicluster engine for Kubernetes 2.11
  • Red Hat OpenShift API for Data Protection 1.3
  • Red Hat OpenShift API for Data Protection 1.4
  • Red Hat OpenShift API for Data Protection 1.5
  • Red Hat OpenShift API for Data Protection 1.6
  • Red Hat Red Hat Advanced Cluster Security 4.9
  • Red Hat Red Hat Advanced Cluster Security for Kubernetes 4.10
  • Red Hat Red Hat Developer Hub 1.10
  • Red Hat Red Hat Developer Hub 1.9
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Migration Toolkit 1.8
  • Red Hat Red Hat Migration Toolkit for Applications 8.1
  • Red Hat Red Hat Migration Toolkit for Applications 8.2
  • Red Hat Red Hat OpenShift AI 2.25
  • Red Hat Red Hat OpenShift AI 3.4
  • Red Hat Red Hat OpenShift Container Platform 4.14
  • Red Hat Red Hat OpenShift Container Platform 4.20
  • Red Hat Red Hat OpenShift Container Platform 4.21
  • Red Hat Red Hat OpenShift Dev Spaces 3.30
  • Red Hat Red Hat OpenShift distributed tracing 3.10.2
  • Red Hat Red Hat OpenShift Service Mesh 3.0
  • Red Hat Red Hat OpenShift Service Mesh 3.1
  • Red Hat Red Hat OpenShift Service Mesh 3.2
  • Red Hat Red Hat OpenShift Service Mesh 3.3

Classification

Weakness
  • CWE-606 Unchecked Input for Loop Condition
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.