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Fencer Vulns
medium 4.4

CVE-2023-4156 json

Heap out of bound read in builtin.c

published 2023-09-25 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-54036

cvss
4.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

A heap out-of-bounds read flaw was found in builtin.c in the gawk package. This issue may lead to a crash and could be used to read sensitive information.

Patch / fix

  • gnu gawk 5.1.1
  • gawk Debian 14, Debian 13, Debian 12 1:5.2.1-1

debian advisories DEBIAN-CVE-2023-4156

  • gawk Ubuntu 20.04 LTS 1:5.0.1+dfsg-1ubuntu0.1
  • gawk Ubuntu 22.04 LTS 1:5.1.0-1ubuntu0.1
  • gawk Ubuntu Pro 14.04 LTS 1:4.0.1+dfsg-2.1ubuntu2+esm1
  • gawk Ubuntu Pro 16.04 LTS 1:4.1.3+dfsg-0.1ubuntu0.1~esm1
  • gawk Ubuntu Pro 18.04 LTS 1:4.1.4+dfsg-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2023-4156

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

  • gawk SLE Module for Basesystem 15 SP5, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +9 more 4.2.1-150000.3.3.1
  • gawk SLES for SAP 12 SP5, SLES 12 SP5 4.1.0-5.3.1

suse advisories SUSE-SU-2023:3440-1SUSE-SU-2023:3431-1

  • gawk CBL-Mariner 2.0 5.1.1-1

azure linux advisories AZL-30045

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2023-4156 updated cvss 6.1

gawk: heap out of bound read in builtin.c

  • Red Hat Enterprise Linux 6 gawk
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 gawk Red Hat Enterprise Linux 8 gawk Red Hat Enterprise Linux 9 gawk, gawk-all-langpacks
    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 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
    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
2 y ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • access.redhat.com https://access.redhat.com/security/cve/CVE-2023-4156 referenced PoC, tagged "exploit" by a source, unverified
  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2215930 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Affected products

  • n/a gawk
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Fedora Fedora

Classification

Weakness

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.