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CVE-2026-98171

HIGHCVSS 8.8/10EPSS 0.21%

Last modified

CVE-2026-98171 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs Fix several related bounds checking and pointer lifecycle issues in receive_encrypted_standard()'s handling of compound encrypted frames: - Clear next_buffer after assigning it to server->bigbuf. A stale next_buffer pointer can lead to a use-after-free on subsequent error paths. - Update pdu_length to the decrypted plaintext size (buf_size). EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs Fix several related bounds checking and pointer lifecycle issues in receive_encrypted_standard()'s handling of compound encrypted frames: - Clear next_buffer after assigning it to server->bigbuf. A stale next_buffer pointer can lead to a use-after-free on subsequent error paths. - Update pdu_length to the decrypted plaintext size (buf_size). Using the pre-decryption length allows NextCommand to point into stale ciphertext residue. - Reject next_cmd values smaller than MID_HEADER_SIZE(server). - Fix an integer overflow in the upper bound check by verifying pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the trailing slice is large enough for a header.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability
0.21%

10.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 72eaef1f37a3b6bec11c342736834dc3707be3e4; >= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 491e33144dee872cffda207f6fcb09260728f803; >= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 8749946579708ea0d339034bb7f423a67dbe89cf; >= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 96c436e4b010711452b2872558938f4ef276492a; >= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 858d5ac22cb889266993e7670f9f0c4f4aeedd78; >= b24df3e30cbf48255db866720fb71f14bf9d2f39, < 05762c5bc1cfdcac36747994fde2c04387a457f1
LinuxLinux4.19

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98171?
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs Fix several related bounds checking and pointer lifecycle issues in receive_encrypted_standard()'s handling of compound encrypted frames: - Clear next_buffer after assigning it to server->bigbuf. A stale next_buffer pointer can lead to a use-after-free on subsequent error paths. - Update pdu_length to the decrypted plaintext size (buf_size). Using the pre-decryption length allows NextCommand to point into stale ciphertext residue. - Reject next_cmd values smaller than MID_HEADER_SIZE(server). - Fix an integer overflow in the upper bound check by verifying pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the trailing slice is large enough for a header.
How severe is CVE-2026-98171?
CVE-2026-98171 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-98171?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST