7.5

CVE-2026-43057: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback

Modified
AliasesUBUNTU-CVE-2026-43057DEBIAN-CVE-2026-43057
Published 01-05-2026Last modified 15-10-2026

Vulnerability summary

CVE-2026-43057 is a high (CVSS 7.5) vulnerability in linux. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 38% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.44%
0%100%
Low · -0.28 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 27 · Related 25
MGASA-2026-0108MGASA-2026-0110OPENSUSE-SU-2026:21388-1SUSE-SU-2026:22742-1SUSE-SU-2026:22769-1SUSE-SU-2026:22809-1

Timeline

  1. 01-05-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers. Packets with extension headers must fall back onto software checksumming. Since TSO depends on checksum offload, those must revert to GSO. The below commit introduces that fallback. It always checks network header length. For tunneled packets, the inner header length must be checked instead. Extend the check accordingly. A special case is tunneled packets without inner IP protocol. Such as RFC 6951 SCTP in UDP. Those are not standard IPv6 followed by transport header either, so also must revert to the software GSO path.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

Decrease -0.28 pp

From 0.72% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu127 products
  • linux< 6.8.0-136.136 | All versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 6.8.0-1061.64 | All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ a0478d7e888028f85fa7785ea838ce0ca09398e2, < 2094a7cf91b71367b649f991aacc7b579f793d0b | ≥ 2156d9e9f2e483c8c3906c0ea57ea312c1424235, < ed71cf465c75f5688b07a35d373cd1d6b589c8ea | ≥ 041e2f945f82fdbd6fff577b79c33469430297aa, < 33670f780e0120c3dacda188c512bbffe0b6044c | ≥ 864e3396976ef41de6cc7bc366276bf4e084fff2, < a98b78116a27e2a57b696b569b2cb431c95cf9b6 | ≥ 864e3396976ef41de6cc7bc366276bf4e084fff2, < 732fdeb2987c94b439d51f5cb9addddc2fc48c42 | ≥ 864e3396976ef41de6cc7bc366276bf4e084fff2, < c4336a07eb6b2526dc2b62928b5104b41a7f81f5 | 794ddbb7b63b6828c75967b9bcd43b086716e7a1 | ≥ 6.1.149, < 6.1.168 | ≥ 6.6.103, < 6.6.134 | ≥ 6.12.44, < 6.12.81 | ≥ 6.16.4, < 6.17 | 6.17
  • linux_kernelEOL≥ 6.1.149, < 6.1.168 | ≥ 6.6.103, < 6.6.134 | ≥ 6.12.44, < 6.12.81 | ≥ 6.16.4, < 6.17 | > 6.17.1, < 6.18.22 | ≥ 6.19, < 6.19.12 | 6.17 | 6.17:rc3 | 6.17:rc4 | 6.17:rc5 | 6.17:rc6 | 6.17:rc7 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5
Debian1 product
  • linux< 6.1.170-1 | < 6.12.85-1 | < 6.19.12-1

3 vendors · 130 products

References

27 links
Show all 27 references