CVE-2025-21629

MEDIUM EPSS 10.9%
Published Jan 15, 20251y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Jan 15, 2025 1y ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
10.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 16

VendorProductVersionRange
linuxlinux_kernel*≥4.19.323  –  <4.20
linuxlinux_kernel*≥5.4.285  –  <5.5
linuxlinux_kernel*≥5.10.229  –  <5.11
linuxlinux_kernel*≥5.15.171  –  <5.16
linuxlinux_kernel*≥6.1.116  –  <6.1.124
linuxlinux_kernel*≥6.6.60  –  <6.6.70
linuxlinux_kernel*≥6.11.7  –  <6.12
linuxlinux_kernel*≥6.12.1  –  <6.12.9
linuxlinux_kernel6.12any
linuxlinux_kernel6.12any
linuxlinux_kernel6.12any
linuxlinux_kernel6.13any
linuxlinux_kernel6.13any
linuxlinux_kernel6.13any
linuxlinux_kernel6.13any
linuxlinux_kernel6.13any

References 5

  • git.kernel.org https://git.kernel.org/stable/c/68e068cabd2c6c533ef934c2e5151609cf6ecc6d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/95ccf006bbc8b59044313b8c309dcf29c546abd4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ac9cfef69565021c9e1022a493a9c40b03e2caf9
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d3b7a9c7597b779039a51d7b34116fbe424bf2b7
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/68e068cabd2c6c533ef934c2e5151609cf6ecc6d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/95ccf006bbc8b59044313b8c309dcf29c546abd4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ac9cfef69565021c9e1022a493a9c40b03e2caf9
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d3b7a9c7597b779039a51d7b34116fbe424bf2b7
    Patch