CVE-2025-21629

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-01-15. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

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 v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

January 15, 2025

Last Modified

August 5, 2026

Advisory Details (5)

Auto-updated Jul 30, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 4076-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
generic

net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d3b7a9c7597b779039a51d7b34116fbe424bf2b7
generic

net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ac9cfef69565021c9e1022a493a9c40b03e2caf9
generic

net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/95ccf006bbc8b59044313b8c309dcf29c546abd4
generic

net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/68e068cabd2c6c533ef934c2e5151609cf6ecc6d

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-21.21) @ oracular2026-05-30ubuntu
ubuntulinux-tools-raspi (6.11.0-1010.10) @ oracular2026-05-30ubuntu
ubuntulinux-tools-lowlatency-64k (6.11.0-1011.12) @ oracular2026-05-30ubuntu
ubuntulinux-tools-oem-24.04b (6.11.0-1017.17) @ noble2026-05-30ubuntu
ubuntulinux-tools-lowlatency-hwe-24.04-edge (6.11.0-1011.12~24.04.1) @ noble2026-05-30ubuntu
linuxKernel @ 6.1.124—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(5)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 10× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 115 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-05 19:16 UTCEPSS rescore
  4. 2026-08-05 14:06 UTCEG score recompute
  5. 2026-08-05 14:06 UTCVendor advisory
  6. 2026-08-05 14:06 UTCGHSA enrichment
  7. 2026-08-04 15:09 UTCEPSS rescore
  8. 2026-08-04 10:37 UTCEPSS rescore
  9. 2026-08-03 10:35 UTCEPSS rescore
  10. 2026-08-02 02:25 UTCEPSS rescore
  11. 2026-08-01 04:15 UTCEPSS rescore
  12. 2026-07-30 16:27 UTCEPSS rescore
  13. 2026-07-30 07:25 UTCEG score recompute
  14. 2026-07-30 07:25 UTCGHSA enrichment
  15. 2026-07-30 01:29 UTCEPSS rescore
  16. 2026-07-28 15:35 UTCEPSS rescore
  17. 2026-07-27 14:12 UTCEPSS rescore
  18. 2026-07-26 14:53 UTCEPSS rescore
  19. 2026-07-25 14:17 UTCEPSS rescore
  20. 2026-07-24 17:41 UTCOSV refresh
  21. 2026-07-24 14:17 UTCEPSS rescore
  22. 2026-07-23 14:17 UTCEPSS rescore
  23. 2026-07-23 02:50 UTCEG score recompute
  24. 2026-07-22 14:07 UTCEPSS rescore
  25. 2026-07-22 14:07 UTCEPSS rescore
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  1. 2026-07-21 15:24 UTCEPSS rescore
  2. 2026-07-20 17:07 UTCEPSS rescore
  3. 2026-07-19 14:30 UTCEPSS rescore
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  5. 2026-07-19 02:28 UTCEPSS rescore
  6. 2026-07-19 02:28 UTCEPSS rescore
  7. 2026-07-18 10:03 UTCEPSS rescore
  8. 2026-07-16 17:02 UTCEPSS rescore
  9. 2026-07-15 16:57 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 01:59 UTCEPSS rescore
  12. 2026-07-13 22:29 UTCEPSS rescore
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  14. 2026-07-13 06:12 UTCEPSS rescore
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  16. 2026-07-12 05:46 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 08:27 UTCEPSS rescore
  19. 2026-07-11 08:26 UTCEPSS rescore
  20. 2026-07-09 19:09 UTCEPSS rescore
  21. 2026-07-08 15:14 UTCEPSS rescore
  22. 2026-07-07 13:45 UTCEPSS rescore
  23. 2026-07-07 13:21 UTCOSV refresh
  24. 2026-07-06 16:26 UTCEPSS rescore
  25. 2026-07-06 02:22 UTCEPSS rescore
  26. 2026-07-06 02:22 UTCEPSS rescore
  27. 2026-07-05 02:30 UTCEPSS rescore
  28. 2026-07-04 06:30 UTCEPSS rescore
  29. 2026-07-01 15:06 UTCEPSS rescore
  30. 2026-06-30 23:21 UTCEPSS rescore
  31. 2026-06-30 23:21 UTCEPSS rescore
  32. 2026-06-29 14:06 UTCEPSS rescore
  33. 2026-06-28 14:07 UTCEPSS rescore
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  35. 2026-06-28 04:55 UTCEPSS rescore
  36. 2026-06-28 04:55 UTCEPSS rescore
  37. 2026-06-27 03:08 UTCEPSS rescore
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  39. 2026-06-25 13:49 UTCEPSS rescore
  40. 2026-06-25 13:49 UTCEPSS rescore
  41. 2026-06-24 14:04 UTCEPSS rescore
  42. 2026-06-24 14:04 UTCEPSS rescore
  43. 2026-06-23 21:32 UTCEPSS rescore
  44. 2026-06-23 21:32 UTCEPSS rescore
  45. 2026-06-22 14:25 UTCEPSS rescore
  46. 2026-06-22 14:25 UTCEPSS rescore
  47. 2026-06-21 14:56 UTCEPSS rescore
  48. 2026-06-21 14:56 UTCEPSS rescore
  49. 2026-06-21 01:59 UTCEPSS rescore
  50. 2026-06-21 01:59 UTCEPSS rescore
  51. 2026-06-19 19:25 UTCEPSS rescore
  52. 2026-06-19 19:25 UTCEPSS rescore
  53. 2026-06-19 00:14 UTCOSV refresh
  54. 2026-06-18 17:52 UTCEPSS rescore
  55. 2026-06-18 17:52 UTCEPSS rescore
  56. 2026-06-17 17:52 UTCEPSS rescore
  57. 2026-06-16 17:52 UTCEPSS rescore
  58. 2026-06-16 17:52 UTCEPSS rescore
  59. 2026-06-15 17:48 UTCEPSS rescore
  60. 2026-06-14 23:17 UTCEPSS rescore
  61. 2026-06-13 22:59 UTCEPSS rescore
  62. 2026-06-12 23:11 UTCEPSS rescore
  63. 2026-06-11 13:59 UTCEPSS rescore
  64. 2026-06-10 22:18 UTCEPSS rescore
  65. 2026-06-10 13:22 UTCEPSS rescore
  66. 2026-06-08 14:16 UTCEPSS rescore
  67. 2026-06-08 14:16 UTCEPSS rescore
  68. 2026-06-07 15:24 UTCEPSS rescore
  69. 2026-06-07 15:24 UTCEPSS rescore
  70. 2026-06-06 13:47 UTCEPSS rescore
  71. 2026-06-06 13:47 UTCEPSS rescore
  72. 2026-06-05 22:46 UTCEPSS rescore
  73. 2026-06-05 22:46 UTCEPSS rescore
  74. 2026-06-05 06:10 UTCEPSS rescore
  75. 2026-06-05 06:10 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-21629?
CVE-2025-21629 is a medium vulnerability published on January 15, 2025. In the Linux kernel, the following vulnerability has been resolved: net: reenable NETIFFIPV6_CSUM offload for BIG TCP packets The blamed commit disabled hardware offoad of IPv6 packets with extension headers on devices that advertise NETIFFIPV6_CSUM, based on the definition of that feature in…
When was CVE-2025-21629 disclosed?
CVE-2025-21629 was first published in the National Vulnerability Database on January 15, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21629 actively exploited?
CVE-2025-21629 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.8% of all scored CVEs.
What is the CVSS score of CVE-2025-21629?
CVE-2025-21629 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21629?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21629, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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