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Fencer Vulns
high 8.1

CVE-2026-87864 json

IMAP APPEND plus CRLF conversion command injection

published 2026-10-20 19 d ago modified 2026-10-30 10 d ago also EUVD-2026-105310

cvss
8.1
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 57%
public exploits
0
none known

Summary

Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the authenticated session.

Patch / fix

  • haxx curl 8.14.3, 8.16.2, 8.20.2, 8.22.0
  • curl Debian 14 8.22.0-1

debian advisories DEBIAN-CVE-2026-87864

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.30
  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.16
  • curl Ubuntu 26.10 8.20.0-2ubuntu11.1
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.8
  • curl Ubuntu Pro 14.04 LTS 7.35.0-1ubuntu2.20+esm24
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm21
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm15
  • curl Ubuntu Pro 20.04 LTS 7.68.0-1ubuntu2.25+esm10

ubuntu advisories UBUNTU-CVE-2026-87864

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl hummingbird 1 8.23.0-0.1.hum1
  • libcurl hummingbird 1 8.23.0-0.1.hum1
  • libcurl-minimal hummingbird 1 8.23.0-0.1.hum1

red hat advisories RHSA-2026:82895

  • curl SLE Module for Basesystem 15 SP7 8.22.0-150700.7.33.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.98.1
  • curl SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 8.0.1-11.134.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.22.0-150600.4.58.1

suse advisories SUSE-SU-2026:5071-1SUSE-SU-2026:5069-1SUSE-SU-2026:5068-1SUSE-SU-2026:4954-1

  • curl openSUSE Tumbleweed 8.23.0-1.1

opensuse advisories openSUSE-SU-2026:12150-1

  • curl Alpine 3.24, Alpine 3.23 8.23.0-r0

alpine advisories ALPINE-CVE-2026-87864

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-2026-87864 updated cvss 3.7

curl: IMAP APPEND plus CRLF conversion command injection

  • Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 curl, libcurl, curl-minimal, libcurl-minimal Red Hat Enterprise Linux 10 curl
    affected: no fix available
  • Red Hat Satellite 6 puppet-agent, openvox-agent
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat Hardened Images curl 8.23.0-0.1.hum1, libcurl 8.23.0-0.1.hum1, libcurl-minimal 8.23.0-0.1.hum1
    fixed: vendor fix RHSA-2026:82895
  • Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, snphost, rust-gdb, +9 more Red Hat Enterprise Linux 10 igvm, rust, snphost, trustee, s390utils Red Hat Hardened Images rust Red Hat JBoss Core Services jbcs-httpd24-curl, jbcs-httpd24-libcurl
    +2 more products
    Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more Red Hat Satellite 6 foreman, foreman-cli, foreman-ec2, foreman-gce, foreman-ovirt, foreman-vmware, +9 more
    not affected: vulnerable code not present

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
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
10 d ago

Exploit prediction

0.83% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3972403 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • curl curl

Classification

Weakness
  • CWE-130 Improper Handling of Length Parameter Inconsistency

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.