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CVE-2026-98171

smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs

No known exploitation. EPSS puts it in the 42nd percentile. Fixed versions are out.

CVSS 3.18.8HighEPSS percentile42nd0.5% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix1 product4 fixed builds listed below

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • LinuxAffected: ≥ b24df3e30cbf48255db866720fb71f14bf9d2f39, < 72eaef1f37a3b6bec11c342736834dc3707be3e4Upgrade to: 72eaef1f37a3b6bec11c342736834dc3707be3e4Affected: ≥ b24df3e30cbf48255db866720fb71f14bf9d2f39, < 491e33144dee872cffda207f6fcb09260728f803Upgrade to: 491e33144dee872cffda207f6fcb09260728f803Affected: ≥ b24df3e30cbf48255db866720fb71f14bf9d2f39, < 8749946579708ea0d339034bb7f423a67dbe89cfUpgrade to: 8749946579708ea0d339034bb7f423a67dbe89cfAffected: ≥ b24df3e30cbf48255db866720fb71f14bf9d2f39, < 96c436e4b010711452b2872558938f4ef276492aUpgrade to: 96c436e4b010711452b2872558938f4ef276492a + 2 more branchesStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS42nd
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.5% chance of exploitation activity in the next 30 days, which ranks it in the 42nd percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

3 events over 1 day, from the signal feeds we watch.

  1. Record updated
  2. Publishedrecord updated

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 8.8 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction RequiredA user must click a link, open a file, or perform some action

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Sources

References in the record

And 3 more references. See all after sign-in

In the news

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