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Fencer Vulns
medium 5.5

CVE-2026-31677 json

crypto: af_alg - limit RX SG extraction by receive buffer budget

published 2026-04-25 6 mo ago modified 2026-11-06 3 d ago also EUVD-2026-25644

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

crypto: af_alg - limit RX SG extraction by receive buffer budget

Make af_alg_get_rsgl() limit each RX scatterlist extraction to the remaining receive buffer budget.

af_alg_get_rsgl() currently uses af_alg_readable() only as a gate before extracting data into the RX scatterlist. Limit each extraction to the remaining af_alg_rcvbuf(sk) budget so that receive-side accounting matches the amount of data attached to the request.

If skcipher cannot obtain enough RX space for at least one chunk while more data remains to be processed, reject the recvmsg call instead of rounding the request length down to zero.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.83, 6.18.24, 6.19.14, 7.0
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.14-1

debian advisories DEBIAN-CVE-2026-31677

  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1046.50
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1061.65

ubuntu advisories UBUNTU-CVE-2026-31677

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

  • kernel RHEL 9 5.14.0-687.5.3.el9_8
  • rv RHEL 9 5.14.0-687.5.3.el9_8
  • perf RHEL 9 5.14.0-687.5.3.el9_8
  • rtla RHEL 9 5.14.0-687.5.3.el9_8
  • libperf RHEL 9 5.14.0-687.5.3.el9_8
  • kernel-rt RHEL 9 5.14.0-687.5.3.el9_8
  • kernel-64k RHEL 9 5.14.0-687.5.3.el9_8
  • kernel-core RHEL 9 5.14.0-687.5.3.el9_8

red hat advisories RHSA-2026:19225RHSA-2026:19074

  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.37.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.37.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1.160000.2.19
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-azure SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-obs-qa SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1

suse advisories SUSE-SU-2026:23237-1SUSE-SU-2026:23068-1SUSE-SU-2026:23221-1SUSE-SU-2026:23231-1SUSE-SU-2026:23066-1SUSE-SU-2026:2914-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.37.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.37.1

opensuse advisories openSUSE-SU-2026:21555-1

  • kernel AlmaLinux 10 6.12.0-211.7.3.el10_2
  • rv AlmaLinux 10 6.12.0-211.7.3.el10_2
  • perf AlmaLinux 10 6.12.0-211.7.3.el10_2
  • rtla AlmaLinux 10 6.12.0-211.7.3.el10_2
  • libperf AlmaLinux 10 6.12.0-211.7.3.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.7.3.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.7.3.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.7.3.el10_2

almalinux advisories ALSA-2026:19074ALSA-2026:19225

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-2026-31677 updated cvss 5.5

kernel: crypto: af_alg - limit RX SG extraction by receive buffer budget

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.5.3.el9_8, perf 5.14.0-687.5.3.el9_8, rtla 5.14.0-687.5.3.el9_8, python3-perf 5.14.0-687.5.3.el9_8, kernel-devel-matched 5.14.0-687.5.3.el9_8, kernel-64k-devel-matched 5.14.0-687.5.3.el9_8, +7 more
    fixed: vendor fix RHSA-2026:19225
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.7.3.el10_2, perf 6.12.0-211.7.3.el10_2, rtla 6.12.0-211.7.3.el10_2, python3-perf 6.12.0-211.7.3.el10_2, kernel-devel-matched 6.12.0-211.7.3.el10_2, kernel-64k-devel-matched 6.12.0-211.7.3.el10_2, +7 more
    fixed: vendor fix RHSA-2026:19074
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.5.3.el9_8, kernel-64k 5.14.0-687.5.3.el9_8, kernel-core 5.14.0-687.5.3.el9_8, kernel-tools 5.14.0-687.5.3.el9_8, kernel-modules 5.14.0-687.5.3.el9_8, kernel-64k-core 5.14.0-687.5.3.el9_8, +27 more
    fixed: vendor fix RHSA-2026:19225
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.7.3.el10_2, kernel-64k 6.12.0-211.7.3.el10_2, kernel-core 6.12.0-211.7.3.el10_2, kernel-tools 6.12.0-211.7.3.el10_2, kernel-modules 6.12.0-211.7.3.el10_2, kernel-64k-core 6.12.0-211.7.3.el10_2, +28 more
    fixed: vendor fix RHSA-2026:19074
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.5.3.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.5.3.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.5.3.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.5.3.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.5.3.el9_8
    fixed: vendor fix RHSA-2026:19225
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.7.3.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.7.3.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.7.3.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.7.3.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.7.3.el10_2
    fixed: vendor fix RHSA-2026:19074
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.5.3.el9_8, kernel-rt-64k 5.14.0-687.5.3.el9_8, kernel-rt-core 5.14.0-687.5.3.el9_8, kernel-rt-modules 5.14.0-687.5.3.el9_8, kernel-rt-64k-core 5.14.0-687.5.3.el9_8, kernel-rt-debug-core 5.14.0-687.5.3.el9_8, +14 more
    fixed: vendor fix RHSA-2026:19225
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.7.3.el10_2, kernel-rt-64k 6.12.0-211.7.3.el10_2, kernel-rt-core 6.12.0-211.7.3.el10_2, kernel-rt-modules 6.12.0-211.7.3.el10_2, kernel-rt-64k-core 6.12.0-211.7.3.el10_2, kernel-rt-debug-core 6.12.0-211.7.3.el10_2, +14 more
    fixed: vendor fix RHSA-2026:19074
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.5.3.el9_8, kernel-rt-core 5.14.0-687.5.3.el9_8, kernel-rt-modules 5.14.0-687.5.3.el9_8, kernel-rt-debug-core 5.14.0-687.5.3.el9_8, kernel-rt-modules-core 5.14.0-687.5.3.el9_8, kernel-rt-debug-modules 5.14.0-687.5.3.el9_8, +4 more
    fixed: vendor fix RHSA-2026:19225
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.7.3.el10_2, kernel-rt-core 6.12.0-211.7.3.el10_2, kernel-rt-modules 6.12.0-211.7.3.el10_2, kernel-rt-debug-core 6.12.0-211.7.3.el10_2, kernel-rt-modules-core 6.12.0-211.7.3.el10_2, kernel-rt-debug-modules 6.12.0-211.7.3.el10_2, +4 more
    fixed: vendor fix RHSA-2026:19074
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 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
3 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

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.