Local kernel panic via IPv6 option-length overflow
Published Apr 13, 2026 · Updated Apr 13, 2026
Integer overflow in the Linux Kernel IPv6 sendmsg ancillary-data path allows local users to crash the system with crafted control messages. ip6_datagram_send_ctl() repeatedly adds IPV6_DSTOPTS lengths to the 16-bit opt_flen field while retaining the final header pointer, so wrapping makes later headroom allocation too small for skb_push(). The path requires CAP_NET_RAW in the target network namespace; root can reach it directly, while an unprivileged local user also can when user namespaces are enabled, and the resulting underflow triggers a kernel BUG and panic.
Summary
What happened
Integer overflow in the Linux Kernel IPv6 sendmsg ancillary-data path allows local users to crash the system with crafted control messages. ip6_datagram_send_ctl() repeatedly adds IPV6_DSTOPTS lengths to the 16-bit opt_flen field while retaining the final header pointer, so wrapping makes later headroom allocation too small for skb_push(). The path requires CAP_NET_RAW in the target network namespace; root can reach it directly, while an unprivileged local user also can when user namespaces are enabled, and the resulting underflow triggers a kernel BUG and panic.
The record
- CVE
- CVE-2026-31415
- Published
- Apr 13, 2026
- Updated
- Apr 13, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-617, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 13, 2026CVE publishedPublication date reported by the CVE source.
- Apr 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.6.14
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <0bdaf54d3aaddfe8df29371260fa8d4939b4fd6f
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <4e453375561fc60820e6b9d8ebeb6b3ee177d42e
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <5e4ee5dbea134e9257f205e31a96040bed71e83f
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <63fda74885555e6bd1623b5d811feec998740ba4
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <872b74900d5daa37067ac676d9001bb929fc6a2a
- Affected versionversion=333fad5364d6b457c8d837f7d05802d2aaf8a961 <9ed81d692758dfb9471d7799b24bfa7a08224c31
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- IPv6 IPV6_DSTOPTS opt_flen wrap proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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