8.2

CVE-2025-21629: linux

CVSS: 8.2v3.1HighModified
AliasesUBUNTU-CVE-2025-21629DEBIAN-CVE-2025-21629
Published 15-01-2025Last modified 05-08-2026
Open JSON

Vulnerability summary

CVE-2025-21629 is a high (CVSS 8.2) vulnerability in linux. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 36% of scored vulnerabilities.

Overall risk
33/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.2/10
010
High · v3.1 (CVE.org)
EPSS score
0.43%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 17 · Related 16
DLA-4076-1MGASA-2025-0030MGASA-2025-0032SUSE-SU-2025:01964-1SUSE-SU-2025:01965-1SUSE-SU-2025:02000-1

Timeline

  1. 15-01-2025
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets The blamed commit disabled hardware offoad of IPv6 packets with extension headers on devices that advertise NETIF_F_IPV6_CSUM, based on the definition of that feature in skbuff.h: * * - %NETIF_F_IPV6_CSUM * - Driver (device) is only able to checksum plain * TCP or UDP packets over IPv6. These are specifically * unencapsulated packets of the form IPv6|TCP or * IPv6|UDP where the Next Header field in the IPv6 * header is either TCP or UDP. IPv6 extension headers * are not supported with this feature. This feature * cannot be set in features for a device with * NETIF_F_HW_CSUM also set. This feature is being * DEPRECATED (see below). The change causes skb_warn_bad_offload to fire for BIG TCP packets. [ 496.310233] WARNING: CPU: 13 PID: 23472 at net/core/dev.c:3129 skb_warn_bad_offload+0xc4/0xe0 [ 496.310297] ? skb_warn_bad_offload+0xc4/0xe0 [ 496.310300] skb_checksum_help+0x129/0x1f0 [ 496.310303] skb_csum_hwoffload_help+0x150/0x1b0 [ 496.310306] validate_xmit_skb+0x159/0x270 [ 496.310309] validate_xmit_skb_list+0x41/0x70 [ 496.310312] sch_direct_xmit+0x5c/0x250 [ 496.310317] __qdisc_run+0x388/0x620 BIG TCP introduced an IPV6_TLV_JUMBO IPv6 extension header to communicate packet length, as this is an IPv6 jumbogram. But, the feature is only enabled on devices that support BIG TCP TSO. The header is only present for PF_PACKET taps like tcpdump, and not transmitted by physical devices. For this specific case of extension headers that are not transmitted, return to the situation before the blamed commit and support hardware offload. ipv6_has_hopopt_jumbo() tests not only whether this header is present, but also that it is the only extension header before a terminal (L4) header.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

0.00 pp

From 0.43% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.43%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu115 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ a84978a9cda68f0afe3f01d476c68db21526baf1, < ac9cfef69565021c9e1022a493a9c40b03e2caf9 | ≥ c69bc67c1cb211aa390bea6e512bb01b1241fefb, < 95ccf006bbc8b59044313b8c309dcf29c546abd4 | ≥ 04c20a9356f283da623903e81e7c6d5df7e4dc3c, < d3b7a9c7597b779039a51d7b34116fbe424bf2b7 | ≥ 04c20a9356f283da623903e81e7c6d5df7e4dc3c, < 68e068cabd2c6c533ef934c2e5151609cf6ecc6d | bcefc3cd7f592a70fcbbbfd7ad1fbc69172ea78b | 477b35d94a21530046fe91589960732fcf2b29ed | a27a5c40ee4cbe00294e2c76160de5f2589061ba | 9f605135a5c0fe614c2b15197b9ced1e217eca59 | 705350fbd6ed4b5d89ee045fa57a0594a72b17d7 | ≥ 6.1.116, < 6.1.124 | ≥ 6.6.60, < 6.6.70 | ≥ 4.19.323, < 4.20 | ≥ 5.4.285, < 5.5 | ≥ 5.10.229, < 5.11 | ≥ 5.15.171, < 5.16 | ≥ 6.11.7, < 6.12 | 6.12
  • linux_kernel≥ 4.19.323, < 4.20 | ≥ 5.4.285, < 5.5 | ≥ 5.10.229, < 5.11 | ≥ 5.15.171, < 5.16 | ≥ 6.1.116, < 6.1.124 | ≥ 6.6.60, < 6.6.70 | ≥ 6.11.7, < 6.12 | ≥ 6.12.1, < 6.12.9 | 6.12 | 6.12:rc6 | 6.12:rc7 | 6.13:rc1 | 6.13:rc2 | 6.13:rc3 | 6.13:rc4 | 6.13:rc5
Debian1 product
  • linux< 6.1.124-1 | < 6.12.9-1

3 vendors · 118 products

References

14 links
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