Linux Kernel up to 7.2-rc3 SCTP sctp_sf_do_5_2_6_stale missing initialization

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7.0	$5k-$25k	2.79

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2-rc3. It has been rated as critical. This issue affects the function sctp_sf_do_5_2_6_stale of the component SCTP. Performing a manipulation results in missing initialization. This vulnerability is reported as CVE-2026-64551. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 7.2-rc3. This affects the function sctp_sf_do_5_2_6_stale of the component SCTP. The manipulation with an unknown input leads to a missing initialization vulnerability. CWE is classifying the issue as CWE-456. The product does not initialize critical variables, which causes the execution environment to use unexpected values. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: sctp: validate STALE_COOKIE cause length before reading staleness When an ERROR chunk with a STALE_COOKIE cause is received in the COOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure of Staleness that follows the cause header: err = (struct sctp_errhdr *)(chunk->skb->data); stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); err is the first cause in the chunk, not the STALE_COOKIE cause that caused the dispatch, and nothing guarantees the staleness field is present. sctp_walk_errors() only requires a cause to be as long as the 4-byte header, so for a STALE_COOKIE cause of length 4 the read runs past the cause, and for a minimal ERROR chunk past skb->tail. The value is echoed to the peer in the Cookie Preservative of the reply INIT, leaking uninitialized memory. sctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so check its length there and pass it to sctp_sf_do_5_2_6_stale(), which reads that cause instead of the first one. A STALE_COOKIE cause too short to hold the staleness field is discarded. The read is reachable by any peer that can drive an association into COOKIE_ECHOED, including an unprivileged process using a raw SCTP socket in a user and network namespace.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-64551 since 07/19/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for 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 07/27/2026).

Upgrading to version 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc4 eliminates this vulnerability. Applying the patch 6022da37786701df1fc5dd946a6dcba59d5473b1/861f884f5471632c731cbbd612a1c072e391a624/588706ebaf8cdb4a4161602949eba365514b1db1/a257b41ddfe9e327b26581ad2777f04b23ac73f5/08a8f2d13f703924316e9aeac863a88ef50990c7/ebe0a55d954fa8da383b6192edb8f763dcb002d5/bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0/1cd23ca80784223fa2204e16203f754da4e821f8 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.260
• 5.15.211
• 6.1.177
• 6.6.144
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
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• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.12.94
• 6.12.95
• 6.12.96
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
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• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
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• 6.18.25
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• 6.18.30
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• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.2-rc1
• 7.2-rc2
• 7.2-rc3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Missing initialization
CWE: CWE-456 / CWE-453
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.261/5.15.212/6.1.178/6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc4
Patch: 6022da37786701df1fc5dd946a6dcba59d5473b1/861f884f5471632c731cbbd612a1c072e391a624/588706ebaf8cdb4a4161602949eba365514b1db1/a257b41ddfe9e327b26581ad2777f04b23ac73f5/08a8f2d13f703924316e9aeac863a88ef50990c7/ebe0a55d954fa8da383b6192edb8f763dcb002d5/bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0/1cd23ca80784223fa2204e16203f754da4e821f8

Timelineinfo

07/19/2026 CVE reserved
07/27/2026 +8 days Advisory disclosed
07/27/2026 +0 days VulDB entry created
07/27/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64551 (🔒)
GCVE (CVE): GCVE-0-2026-64551
GCVE (VulDB): GCVE-100-383607

Entryinfo

Created: 07/27/2026 23:26
Changes: 07/27/2026 23:26 (59)
Complete: 🔍
Cache ID: 216::103

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