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Fencer Vulns
medium 5.3

CVE-2026-39819 json

Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go

published 2026-05-07 6 mo ago modified 2026-09-22 48 d ago also BIT-golang-2026-39819 , EUVD-2026-28422 , GO-2026-4978

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

The "go bug" command writes to two files with predictable names in the system temporary directory (for example, "/tmp"). An attacker with access to the temporary directory can create a symlink in one of these names, causing "go bug" to overwrite the target of the symlink.

Patch / fix

  • bitnami golang 1.25.10, 1.26.3
  • go toolchain 1.25.10, 1.26.3
  • Go toolchain cmd/go 1.25.10, 1.26.3
  • golang-1.26 Debian 14 1.26.3-1

debian advisories DEBIAN-CVE-2026-39819

  • golang1.27 hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-bin hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-src hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-misc hummingbird 1 1.27.1-0.1.hum1
  • golang1.27-tests hummingbird 1 1.27.1-0.1.hum1
  • golang1.26 hummingbird 1 1.26.8-0.1.hum1
  • golang1.26-bin hummingbird 1 1.26.8-0.1.hum1
  • golang1.26-src hummingbird 1 1.26.8-0.1.hum1

red hat advisories RHSA-2026:66561RHSA-2026:62391RHSA-2026:61253RHSA-2026:57649RHSA-2026:49712RHSA-2026:49702

  • 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

  • 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-2026:21483-1openSUSE-SU-2026:21319-1openSUSE-SU-2026:21254-1openSUSE-SU-2026:10741-1openSUSE-SU-2026:10723-1

  • delve AlmaLinux 8 1.25.2-1.module_el8.10.0+4074+24330916
  • golang AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • go-toolset AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • golang-bin AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • golang-src AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • golang-misc AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • golang-race AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4
  • golang-tests AlmaLinux 8 1.25.10-1.module_el8.10.0+4187+c45165c4

almalinux advisories ALSA-2026:22112ALSA-2026:22121

  • golang Rocky Linux 10 1.26.3-4.el10_2
  • golang Rocky Linux 9 1.26.3-1.el9_8
  • delve Rocky Linux 8 1.25.2-1.module+el8.10.0+40035+ee0a7047
  • golang Rocky Linux 8 1.25.10-1.module+el8.10.0+40200+0fd0f175

rocky linux advisories RLSA-2026:22120RLSA-2026:22121RLSA-2026:22112

  • 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-2026-39819

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-2026-39819 updated cvss 4.4

cmd/go: golang: Go 'go bug' command: Arbitrary file overwrite via symlink attack

  • Red Hat Hardened Images golang1.25
    affected: no fix planned “Will not fix”
  • 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/backplane-rhel9-operator, multicluster-engine/multicloud-manager-rhel9, +3 more Red Hat OpenShift API for Data Protection oadp/oadp-velero-rhel9 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/config-policy-controller-rhel9, rhacm2/klusterlet-addon-controller-rhel9, rhacm2/governance-policy-propagator-rhel9, rhacm2/acm-governance-policy-framework-addon-rhel9, rhacm2/acm-governance-policy-addon-controller-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-hypershift-rhel9
    under investigation
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/hypershift-addon-rhel9-operator 1786912006
    fixed: vendor fix RHSA-2026:57194
  • Red Hat Enterprise Linux AppStream (v. 8) delve 1.25.2-1.module+el8.10.0+23746+9db33b5e, golang 1.25.10-1.module+el8.10.0+24308+5c4a16b7, go-toolset 1.25.10-1.module+el8.10.0+24308+5c4a16b7, golang-bin 1.25.10-1.module+el8.10.0+24308+5c4a16b7, golang-src 1.25.10-1.module+el8.10.0+24308+5c4a16b7, golang-misc 1.25.10-1.module+el8.10.0+24308+5c4a16b7, +2 more
    fixed: vendor fix RHSA-2026:22112
  • Red Hat Enterprise Linux AppStream (v. 9) golang 1.26.3-1.el9_8, go-toolset 1.26.3-1.el9_8, golang-bin 1.26.3-1.el9_8, golang-src 1.26.3-1.el9_8, golang-misc 1.26.3-1.el9_8, golang-race 1.26.3-1.el9_8, +1 more
    fixed: vendor fix RHSA-2026:22121
  • Red Hat Enterprise Linux AppStream (v. 10) golang 1.26.3-4.el10_2, go-toolset 1.26.3-4.el10_2, golang-bin 1.26.3-4.el10_2, golang-src 1.26.3-4.el10_2, golang-misc 1.26.3-4.el10_2, golang-race 1.26.3-4.el10_2, +1 more
    fixed: vendor fix RHSA-2026:22120
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) golang 1.26.5-1.el9_2, go-toolset 1.26.5-1.el9_2, golang-bin 1.26.5-1.el9_2, golang-src 1.26.5-1.el9_2, golang-misc 1.26.5-1.el9_2, golang-race 1.26.5-1.el9_2, +1 more
    fixed: vendor fix RHSA-2026:61253
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) golang 1.26.5-1.el9_4, go-toolset 1.26.5-1.el9_4, golang-bin 1.26.5-1.el9_4, golang-src 1.26.5-1.el9_4, golang-misc 1.26.5-1.el9_4, golang-race 1.26.5-1.el9_4, +1 more
    fixed: vendor fix RHSA-2026:57649
show 4 more
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) golang 1.26.5-1.el10_0, go-toolset 1.26.5-1.el10_0, golang-bin 1.26.5-1.el10_0, golang-src 1.26.5-1.el10_0, golang-misc 1.26.5-1.el10_0, golang-race 1.26.5-1.el10_0, +1 more
    fixed: vendor fix RHSA-2026:49702
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) golang 1.26.5-1.el9_6, go-toolset 1.26.5-1.el9_6, golang-bin 1.26.5-1.el9_6, golang-src 1.26.5-1.el9_6, golang-misc 1.26.5-1.el9_6, golang-race 1.26.5-1.el9_6, +1 more
    fixed: vendor fix RHSA-2026:49712
  • Red Hat Hardened Images golang1.26 1.26.8-0.1.hum1, golang1.27 1.27.1-0.1.hum1, golang1.26-bin 1.26.8-0.1.hum1, golang1.26-src 1.26.8-0.1.hum1, golang1.27-bin 1.27.1-0.1.hum1, golang1.27-src 1.27.1-0.1.hum1, +4 more
    fixed: vendor fix RHSA-2026:62391
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/hive-rhel9 1786947450, multicluster-engine/work-rhel9 1786907276, multicluster-engine/discovery-rhel9 1786911975, multicluster-engine/placement-rhel9 1786911984, multicluster-engine/console-mce-rhel9 1786911977, multicluster-engine/must-gather-rhel9 1786911926, +25 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
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
NVD 3.1 5.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
CNA 3.1 5.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
OSV 3.1 5.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N

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 toolchain
<1.25.10
>=1.26.0-0, <1.26.3
1.25.10
1.26.3

Affected products

  • Go toolchain cmd/go

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access

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.