CVE-2026-68302amt: re-read skb header pointers after every pull
- 9.8CriticalCVSS base score
- 0.48%Exploitation in 30 daysEPSS · top 58% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: amt: re-read skb header pointers after every pull Several AMT receive and transmit paths cache a pointer into the skb head (ip_hdr(), ipv6_hdr(), eth_hdr() or the AMT message header) and then call a helper that can reallocate that head before the cached pointer is used again. pskb_may_pull(), ip_mc_may_pull(), ipv6_mc_may_pull(), iptunnel_pull_header(), ip_mc_check_igmp() and ipv6_mc_check_mld() can all free the old head and move the data, so a pointer taken before the call dangles afterwards and the later access is a use-after-free of the freed head. The affected sites are: amt_rcv() caches ip_hdr() before amt_parse_type() pulls, then reads iph->saddr. amt_dev_xmit() caches ip_hdr()/ipv6_hdr() before ip_mc_check_igmp()/ ipv6_mc_check_mld() and pskb_may_pull(), then reads the group address. amt_multicast_data_handler() caches eth_hdr() before pskb_may_pull(), then writes the L2 header. amt_membership_query_handler() caches the AMT header, the outer and inner eth_hdr() and ip_hdr() before iptunnel_pull_header() and several pulls, then reads and writes them. amt_igmpv3_report_handler() and amt_mldv2_report_handler() cache ip_hdr()/ipv6_hdr() and the current group record and read the record count from the report header inside the record loop, across the *_mc_may_pull() calls. amt_update_handler() caches ip_hdr() and the AMT membership-update header before pskb_may_pull(), iptunnel_pull_header(), ip_mc_check_igmp() and the report handler, then reads iph->daddr and amtmu->nonce / amtmu->response_mac. Fix each site by either snapshotting the scalar that is used after the pull before the first pull runs, or re-deriving the header pointer from the skb after the last pull that can move the head. Values that are stable across the pull (source and group address, the response MAC and nonce, the record count, the outer source MAC) are snapshotted; pointers that are written through or read repeatedly are re-derived.
Timeline
ID reserved
By Linux
- 11 days later
· 11 days later
Published
- 9 days later
· 9 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.48% · top 58% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < 37ff890f9c18dfbcf57e17199901d4fd1e4c174e
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < 9005b221cb1f9c3c1a2ef656fb0e8fa80c0a187e
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < 7746d588d42a4ac0117b68ed8e9b22a9da53dfb7
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < ca0e8b661957f777591efe874cd9d9a63619cd99
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < 7f48e3ddad8e97545b25788b8203b3a539df1621
- affected cbc21dc1cfe949e37b2a54c71511579f1899e8d4 – < 3656a79f94c471827a08f2cacce5f94ad5e52c24
- affected 5.16
- unaffected < 5.16
- unaffected 6.1.183 – ≤ 6.1.*
- unaffected 6.6.148 – ≤ 6.6.*
- unaffected 6.12.101 – ≤ 6.12.*
- unaffected 6.18.42 – ≤ 6.18.*
- unaffected 7.1.6 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/37ff890f9c18dfbcf57e17199901d4fd1e4c174e (opens in a new tab)
- https://git.kernel.org/stable/c/9005b221cb1f9c3c1a2ef656fb0e8fa80c0a187e (opens in a new tab)
- https://git.kernel.org/stable/c/7746d588d42a4ac0117b68ed8e9b22a9da53dfb7 (opens in a new tab)
- https://git.kernel.org/stable/c/ca0e8b661957f777591efe874cd9d9a63619cd99 (opens in a new tab)
- https://git.kernel.org/stable/c/7f48e3ddad8e97545b25788b8203b3a539df1621 (opens in a new tab)
- https://git.kernel.org/stable/c/3656a79f94c471827a08f2cacce5f94ad5e52c24 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-55403 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-68302)Record last updated .