Linux Kernel up to 7.1.9 s390 vfio_ccw ccwchain_calc_length out-of-bounds

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.5$0-$5k0.60

Summaryinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.1.9. This vulnerability affects the function ccwchain_calc_length of the component s390 vfio_ccw. The manipulation leads to out-of-bounds. This vulnerability is traded as CVE-2026-80550. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.1.9. This issue affects the function ccwchain_calc_length of the component s390 vfio_ccw. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Fix out of bounds check on CCW array The routine ccwchain_calc_length() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs. The loop itself is "do..while (count < 257)", and while the logic in is_cpa_within_range() correctly adjusts between the 0-index array of CCWs and the count of CCWs starting at 1, this means it would look at a possible 257th CCW before ending the loop and (correctly) returning an error. Fix this by restructuring the loop to break as soon as 256 CCWs (thus indexes 0-255) are examined, without looking at memory outside the range.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-80550 since 08/26/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/26/2026).

Upgrading to version 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46 or 7.1.10 eliminates this vulnerability. Applying the patch 907adc667d902fafbdb2d740d57b55bd025dc4cd/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3/af3f80ca4c8b17f20f9e588def076288fdb49e65/499a8a66b1598bfab97182aed15e0f1646074a3d/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb/d5d096cd9369e986d4e5153baa86b8b35c283e09/a005b7f1a491ffda61bff0fd0f6548f8986fb977 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best 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: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.266/5.15.217/6.1.184/6.6.153/6.12.105/6.18.46/7.1.10
Patch: 907adc667d902fafbdb2d740d57b55bd025dc4cd/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3/af3f80ca4c8b17f20f9e588def076288fdb49e65/499a8a66b1598bfab97182aed15e0f1646074a3d/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb/d5d096cd9369e986d4e5153baa86b8b35c283e09/a005b7f1a491ffda61bff0fd0f6548f8986fb977

Timelineinfo

08/26/2026 Advisory disclosed
08/26/2026 +0 days CVE reserved
08/26/2026 +0 days VulDB entry created
08/26/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-80550 (🔒)
GCVE (CVE): GCVE-0-2026-80550
GCVE (VulDB): GCVE-100-395849

Entryinfo

Created: 08/26/2026 17:37
Changes: 08/26/2026 17:37 (59)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Are you interested in using VulDB?

Download the whitepaper to learn more about our service!