Linux Kernel up to 6.6.159/6.12.112/6.18.56/7.2.10 strparser strp_done use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.78

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel up to 6.6.159/6.12.112/6.18.56/7.2.10. Impacted is the function strp_done of the component strparser. The manipulation leads to use after free. This vulnerability is listed as CVE-2026-99056. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.159/6.12.112/6.18.56/7.2.10 and classified as very critical. This issue affects the function strp_done of the component strparser. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: strparser: make sure __strp_recv isn't running before tearing down the parser The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done(). This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed. Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug. This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it. Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause(). A reproducer has been published and turns the possible UAF into an exploit [1].

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-99056 since 09/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/23/2026).

Upgrading to version 6.6.160, 6.12.113, 6.18.57 or 7.2.11 eliminates this vulnerability. Applying the patch a18dd388045dc7263d99a07db9de4e0f149ca8f1/9f3e9fe1b155e9b4572054d8d140586bc3512ecf/d2b5f637b9b67a79a50d42614d10653c13b4e449/eaa3a29004c063d7e9d5ea55636f693f67e6db0f/0984ebc631792acf8fff105112ee74a6b8f1efcc is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.160/6.12.113/6.18.57/7.2.11
Patch: a18dd388045dc7263d99a07db9de4e0f149ca8f1/9f3e9fe1b155e9b4572054d8d140586bc3512ecf/d2b5f637b9b67a79a50d42614d10653c13b4e449/eaa3a29004c063d7e9d5ea55636f693f67e6db0f/0984ebc631792acf8fff105112ee74a6b8f1efcc

Timelineinfo

09/25/2026 CVE reserved
10/23/2026 +28 days Advisory disclosed
10/23/2026 +0 days VulDB entry created
10/23/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-99056 (🔒)
GCVE (CVE): GCVE-0-2026-99056
GCVE (VulDB): GCVE-100-425903

Entryinfo

Created: 10/23/2026 15:51
Changes: 10/23/2026 15:51 (59)
Complete: 🔍
Cache ID: 216::103

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