Remote system crash via undersized ESP page fragment
Published Jul 19, 2026 · Updated Jul 19, 2026
Memory corruption in Linux Kernel ESP allows remote attackers to crash systems via crafted IPv4 or IPv6 IPsec traffic. esp_output_head() tests payload and trailer lengths separately, but esp_output_tail() allocates one page fragment for their aligned post-trailer sum, letting the destination scatterlist extend past that page. The flaw is reachable without authentication when outbound ESP processing enters the out-of-place page-fragment fast path, and a successful trigger can corrupt kernel memory and interrupt the system.
Summary
What happened
Memory corruption in Linux Kernel ESP allows remote attackers to crash systems via crafted IPv4 or IPv6 IPsec traffic. esp_output_head() tests payload and trailer lengths separately, but esp_output_tail() allocates one page fragment for their aligned post-trailer sum, letting the destination scatterlist extend past that page. The flaw is reachable without authentication when outbound ESP processing enters the out-of-place page-fragment fast path, and a successful trigger can corrupt kernel memory and interrupt the system.
The record
- CVE
- CVE-2026-63912
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 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=2c66b0c95bb0aa7652ba1eba293d0d5993b35a38
- Affected versionversion=3defefd22ad5fbbe639b6157fb7e6311b2bf333d
- Affected versionversion=4.14.288 <4.15
- Affected versionversion=4.19.252 <4.20
- Affected versionversion=5.10.113 <5.10.259
- Affected versionversion=5.15.36 <5.15.210
- Affected versionversion=5.17.5 <5.18
- Affected versionversion=5.18
- Affected versionversion=5.4.205 <5.5
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <322e48187e0245ab2fff6fec2220b0cae677dbec
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <36519e3d941fc99d3b52c134dbaf311f987a4708
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <65f3b3fc2347b89fe21db1e92c7681368415f095
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <b84091ceddc9f133229dceab3ccc930bf27f9cba
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <c093468aea8277f77272a4f199b2e15e19cabb59
- Affected versionversion=5bd8baab087dff657e05387aee802e70304cc813 <dfa0d7b0ff1eb6b2c416b8fdb9b4f2cefba57a40
- Affected versionversion=a583f2f3c8788bffd7fd7baeb76bd6d80543d7ea <5d7ab86e2b6bc23054616bf6ac562013bf60af8c
- Affected versionversion=b657030870bb5351c5b1e84d4e9f186da6ca0496
- Affected versionversion=c075c3ea031757f8ea2d34567565b61a868c08d5 <566295735530ee513326049b0540f32ec050bf2e
- Affected versionversion=ef6f83df1209a7d9bd1c605a62457d4c00f9179e
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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