Remote service interruption via stale connection counts
Published May 27, 2026 · Updated May 27, 2026
Connection-counting error in Linux Kernel 5.19 and affected stable releases allows remote attackers to block new service connections. nf_conncount skips garbage collection after one run per jiffy, so bursts above eight new connections leave stale entries and falsely exhaust the configured limit. Reachability requires nft_connlimit, xt_connlimit, or an OVS connection limit; sustained traffic then rejects legitimate new connections without data exposure or modification.
Summary
What happened
Connection-counting error in Linux Kernel 5.19 and affected stable releases allows remote attackers to block new service connections. nf_conncount skips garbage collection after one run per jiffy, so bursts above eight new connections leave stale entries and falsely exhaust the configured limit. Reachability requires nft_connlimit, xt_connlimit, or an OVS connection limit; sustained traffic then rejects legitimate new connections without data exposure or modification.
The record
- CVE
- CVE-2026-45860
- Published
- May 27, 2026
- Updated
- May 27, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 27, 2026CVE publishedPublication date reported by the CVE source.
- May 27, 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=5.10.248 <5.10.252
- Affected versionversion=5.15.198 <5.15.202
- Affected versionversion=5.19
- Affected versionversion=be69850b461e7b491d87a22e33ab76fdd04b725e <13eede458fdf231f1bf96a398feea4ad1553f14c
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <0792ad077d776c2dcf20f0484e2461ded1b77a24
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <0af0812baf2d363176c9b76fc07e33f13aede8db
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <21d033e472735ecec677f1ae46d6740b5e47a4f3
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <3d0994ed0aa1fc0a2c5e620b765e8defdd021bff
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <6e5fa7add3e76da068a478d905be64be8fa4e80a
- Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <fa85432d58c8e74b39333edbf8d28df2985dfc79
- Affected versionversion=f106694733c66a48740c25bc4e212e9b2ea364ce <a5c9e14e0e8923218ae881d5e78c990c07694966
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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