Service interruption via unsynchronized TCP sysctl reads
Published Feb 26, 2025 · Updated May 23, 2026
A race condition in the Linux TCP stack allows local users to interrupt service by changing tcp_min_snd_mss during concurrent reads. Readers in net/ipv4/tcp_output.c and net/ipv4/tcp_timer.c access the shared sysctl without READ_ONCE, so a concurrent write can produce an inconsistent value. Exploitation requires low local privileges and precise timing; the documented consequence is availability loss, with no reported data disclosure or modification.
Summary
What happened
A race condition in the Linux TCP stack allows local users to interrupt service by changing tcp_min_snd_mss during concurrent reads. Readers in net/ipv4/tcp_output.c and net/ipv4/tcp_timer.c access the shared sysctl without READ_ONCE, so a concurrent write can produce an inconsistent value. Exploitation requires low local privileges and precise timing; the documented consequence is availability loss, with no reported data disclosure or modification.
The record
- CVE
- CVE-2022-49596
- Published
- Feb 26, 2025
- Updated
- May 23, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-362, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 26, 2025CVE publishedPublication date reported by the CVE source.
- May 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2efabe3e1491f10bf3cf82ae1a371755ba054a1b
- Affected versionversion=3.16.69 <3.17
- Affected versionversion=4.14.127 <4.15
- Affected versionversion=4.19.52 <4.20
- Affected versionversion=4.4.182 <4.5
- Affected versionversion=4.9.182 <4.10
- Affected versionversion=5.1.11 <5.2
- Affected versionversion=5.2
- Affected versionversion=5f3e2bf008c2221478101ee72f5cb4654b9fc363 <0d8a39feb58910a7f7746b1770ee5578cc551fe6
- Affected versionversion=5f3e2bf008c2221478101ee72f5cb4654b9fc363 <0fc9357282df055e30990b29f4b7afa53ab42cdb
- Affected versionversion=5f3e2bf008c2221478101ee72f5cb4654b9fc363 <78eb166cdefcc3221c8c7c1e2d514e91a2eb5014
- Affected versionversion=5f3e2bf008c2221478101ee72f5cb4654b9fc363 <97992e8feff33b3ae154a113ec398546bbacda80
- Affected versionversion=5f3e2bf008c2221478101ee72f5cb4654b9fc363 <fdb96b69f5909ffcdd6f1e0902219fc6d7689ff7
- Affected versionversion=6b7e7997ad3505db7de85ff12276fc84659481d3
- Affected versionversion=7f9f8a37e563c67b24ccd57da1d541a95538e8d9
- Affected versionversion=8e39cbc03dafa3731d22533f869bf326c0e6e6f8
- Affected versionversion=cd6f35b8421ff20365ff711c0ac7647fd70e9af7
- Affected versionversion=e757d052f3b8ce739d068a1e890643376c16b7a9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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