CVE-2025-37756

Kernel memory disclosure and corruption via kTLS disconnect

Published May 1, 2025 · Updated Aug 5, 2026

Use-after-free in Linux kernel kTLS starting in 4.13 allows local users to read kernel memory, corrupt the heap, or crash the system. After a kTLS socket latches a borrowed frag_list, AF_UNSPEC disconnect frees the skbuff chain while the strparser retains it for recvmsg(). Any local user can invoke the ordinary socket sequence when the TLS module is built in or loaded, enabling disclosure and memory-corruption primitives.

CVSS severity7.8
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel kTLS starting in 4.13 allows local users to read kernel memory, corrupt the heap, or crash the system. After a kTLS socket latches a borrowed frag_list, AF_UNSPEC disconnect frees the skbuff chain while the strparser retains it for recvmsg(). Any local user can invoke the ordinary socket sequence when the TLS module is built in or loaded, enabling disclosure and memory-corruption primitives.

The record

CVE
CVE-2025-37756
Published
May 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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.

  1. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <2bcad8fefcecdd5f005d8c550b25d703c063c34a
  2. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <5071a1e606b30c0c11278d3c6620cd6a24724cf6
  3. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf
  4. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <8513411ec321942bd3cfed53d5bb700665c67d86
  5. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <9fcbca0f801580cbb583e9cb274e2c7fbe766ca6
  6. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <ac91c6125468be720eafde9c973994cb45b61d44
  7. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <c665bef891e8972e1d3ce5bbc0d42a373346a2c3
  8. Affected versionversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <f3ce4d3f874ab7919edca364c147ac735f9f1d04
  9. Affected versionversion=4.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <2bcad8fefcecdd5f005d8c550b25d703c063c34a; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <5071a1e606b30c0c11278d3c6620cd6a24724cf6; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <8513411ec321942bd3cfed53d5bb700665c67d86; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <9fcbca0f801580cbb583e9cb274e2c7fbe766ca6; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <ac91c6125468be720eafde9c973994cb45b61d44; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <c665bef891e8972e1d3ce5bbc0d42a373346a2c3; version=3c4d7559159bfe1e3b94df3a657b2cda3a34e218 <f3ce4d3f874ab7919edca364c147ac735f9f1d04; version=4.13

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.3OracleCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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