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Fencer Vulns
critical 9.8

CVE-2026-53151 in the critical feed json

rxrpc: Fix the ACK parser to extract the SACK table for parsing

published 2026-06-25 4 mo ago modified 2026-10-19 20 d ago also EUVD-2026-39242

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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

rxrpc: Fix the ACK parser to extract the SACK table for parsing

Fix modification of the received skbuff in rxrpc_input_soft_acks() and a potential incorrect access of the buffer in a fragmented UDP packet (the packet would probably have to be deliberately pre-generated as fragmented) when AF_RXRPC tries to extract the contents of the SACK table by copying out the contents of the SACK table into a buffer before attempting to parse

AF_RXRPC assumes that it can just call skb_condense() and then validly access the SACK table from skb->data and that it will be a flat buffer - but skb_condense() can silently fail to do anything under some circumstances.

Note that whilst rxrpc_input_soft_acks() should be able to parse extended ACKs, the rest of AF_RXRPC doesn't currently support that.

Further, there's then no need to call skb_condense() in rxrpc_input_ack(), so don't.

Patch / fix

  • Linux Linux 6.6.144, 6.12.95, 6.18.36, 7.0.13, 7.1
  • linux Debian 13 6.12.95-1
  • linux Debian 14 7.0.13-1

debian advisories DEBIAN-CVE-2026-53151

  • linux Ubuntu 24.04 LTS 6.8.0-137.137
  • linux Ubuntu 26.04 LTS 7.0.0-29.29
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1062.65
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1065.73
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1060.68
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1005.6

ubuntu advisories UBUNTU-CVE-2026-53151

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 Azure Linux 3.0 6.6.144.1-1

azure linux advisories AZL-90306

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-2026-53151 updated cvss 8.1

kernel: rxrpc: Fix the ACK parser to extract the SACK table for parsing

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available
  • 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 Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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
yes
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
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.