Skip to content
Fencer Vulns
high 7.1

CVE-2022-49340 json

ip_gre: test csum_start instead of transport header

published 2025-02-26 20 mo ago modified 2026-08-05 3 mo ago also EUVD-2022-54888

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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

ip_gre: test csum_start instead of transport header

GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets.

ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was

if (csum && skb_checksum_start(skb) < skb->data) return -EINVAL;

This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward

if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) < skb->data) return -EINVAL;

But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath.

Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection.

Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured.

Patch / fix

  • Linux Linux 4.19.247, 5.4.198, 5.10.122, 5.15, 5.15.47, 5.17.15, 5.18.4, 5.19
  • linux Debian 14, Debian 13, Debian 12 5.18.5-1

debian advisories DEBIAN-CVE-2022-49340

  • linux Ubuntu 18.04 LTS 4.15.0-192.203
  • linux Ubuntu 20.04 LTS 5.4.0-126.142
  • linux Ubuntu 22.04 LTS 5.15.0-48.54
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1140.151
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1085.92
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1020.24
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1089.97
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1018.24

ubuntu advisories UBUNTU-CVE-2022-49340

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 5.14.0-162.6.1.el9_1
  • perf RHEL 9 5.14.0-162.6.1.el9_1
  • bpftool RHEL 9 5.14.0-162.6.1.el9_1
  • kernel-core RHEL 9 5.14.0-162.6.1.el9_1
  • kernel-tools RHEL 9 5.14.0-162.6.1.el9_1
  • python3-perf RHEL 9 5.14.0-162.6.1.el9_1
  • kernel-modules RHEL 9 5.14.0-162.6.1.el9_1
  • kernel-zfcpdump RHEL 9 5.14.0-162.6.1.el9_1

red hat advisories RHSA-2022:8267

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-2022-49340 updated cvss 5.5

kernel: ip_gre: test csum_start instead of transport header

  • 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
    affected: no fix planned “Out of support scope”
  • 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 CodeReady Linux Builder (v. 9) kernel-debuginfo-common-s390x 5.14.0-162.6.1.el9_1, kernel-debuginfo-common-x86_64 5.14.0-162.6.1.el9_1, kernel-debuginfo-common-aarch64 5.14.0-162.6.1.el9_1, kernel-debuginfo-common-ppc64le 5.14.0-162.6.1.el9_1 Red Hat Enterprise Linux AppStream (v. 9) perf 5.14.0-162.6.1.el9_1, kernel-devel-matched 5.14.0-162.6.1.el9_1, kernel-debug-devel-matched 5.14.0-162.6.1.el9_1, kernel-debuginfo-common-s390x 5.14.0-162.6.1.el9_1, kernel-zfcpdump-devel-matched 5.14.0-162.6.1.el9_1, kernel-debuginfo-common-x86_64 5.14.0-162.6.1.el9_1, +2 more Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-162.6.1.el9_1, bpftool 5.14.0-162.6.1.el9_1, kernel-core 5.14.0-162.6.1.el9_1, kernel-tools 5.14.0-162.6.1.el9_1, python3-perf 5.14.0-162.6.1.el9_1, kernel-modules 5.14.0-162.6.1.el9_1, +14 more
    fixed: vendor fix RHSA-2022:8267
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 10 kernel
    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

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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