CVE-2022-49768Network attack vector

Remote service hang via recursive client lock

Published May 1, 2025 · Updated Aug 5, 2026

Improper locking in the Linux kernel 9p fd transport allows remote attackers controlling a mounted 9p server to hang client operations. The p9_conn_cancel path retains client->lock while p9_client_cb calls p9_req_put and p9_tag_remove, which acquire the same nonrecursive lock again. An established TCP or Unix 9p mount to the attacker-controlled server is required; crafted replies or connection errors deadlock the worker and stop further 9p operations without disclosing or changing data.

CVSS severity7.5
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the Linux kernel 9p fd transport allows remote attackers controlling a mounted 9p server to hang client operations. The p9_conn_cancel path retains client->lock while p9_client_cb calls p9_req_put and p9_tag_remove, which acquire the same nonrecursive lock again. An established TCP or Unix 9p mount to the attacker-controlled server is required; crafted replies or connection errors deadlock the worker and stop further 9p operations without disclosing or changing data.

The record

CVE
CVE-2022-49768
Published
May 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.14.70 <4.14.300
  2. Affected versionversion=4.18.8 <4.19
  3. Affected versionversion=4.19
  4. Affected versionversion=4.9.127 <4.9.334
  5. Affected versionversion=4cd195263e420311d31451cc053fde8037f326f1 <e3031280fe4eaf61a09e60823331f81f321be8e1
  6. Affected versionversion=91ca7c5644c370dc5132b1db1aea81416a4b2181
  7. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <52f1c45dde9136f964d63a77d19826c8a74e2c7f
  8. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <612c977f5d481f551d03d83d0aef588845c1300c
  9. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <96760723aae1b45f733f702abb4333137143909f
  10. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <a4f1a01b2e81378fce9ca528d4d8a049e4b58fcd
  11. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <f14858bc77c567e089965962877ee726ffad0556
  12. Affected versionversion=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <fec1406f5e7ab20b71f6d231792b0040e3300aaf
  13. Affected versionversion=eb1ca07f4343b4e58b97e792a85d5ba1ba103f5d <82825dbf393f7c7979d462f9609a15bde8092b3f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.14.70 <4.14.300; version=4.18.8 <4.19; version=4.19; version=4.9.127 <4.9.334; version=4cd195263e420311d31451cc053fde8037f326f1 <e3031280fe4eaf61a09e60823331f81f321be8e1; version=91ca7c5644c370dc5132b1db1aea81416a4b2181; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <52f1c45dde9136f964d63a77d19826c8a74e2c7f; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <612c977f5d481f551d03d83d0aef588845c1300c; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <96760723aae1b45f733f702abb4333137143909f; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <a4f1a01b2e81378fce9ca528d4d8a049e4b58fcd; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <f14858bc77c567e089965962877ee726ffad0556; version=9f476d7c540cb57556d3cc7e78704e6cd5100f5f <fec1406f5e7ab20b71f6d231792b0040e3300aaf; version=eb1ca07f4343b4e58b97e792a85d5ba1ba103f5d <82825dbf393f7c7979d462f9609a15bde8092b3f

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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