Local service interruption via uninitialized IPVS source address
Published May 20, 2025 · Updated May 23, 2026
Use of an uninitialized resource in affected Linux kernel versions allows local users to interrupt IPVS tunnel routing. In net/netfilter/ipvs/ip_vs_xmit.c, do_output_route4 reads the saddr input even though the tunnel path should ignore it, so an uninitialized address can block route connection. Low-privileged local access and an active IPVS tunnel path are required; the demonstrated consequence is loss of route connectivity rather than data disclosure or modification.
Summary
What happened
Use of an uninitialized resource in affected Linux kernel versions allows local users to interrupt IPVS tunnel routing. In net/netfilter/ipvs/ip_vs_xmit.c, do_output_route4 reads the saddr input even though the tunnel path should ignore it, so an uninitialized address can block route connection. Low-privileged local access and an active IPVS tunnel path are required; the demonstrated consequence is loss of route connectivity rather than data disclosure or modification.
The record
- CVE
- CVE-2025-37961
- Published
- May 20, 2025
- Updated
- May 23, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-908, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 20, 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=212c45ac20229c1752dd56fa38e9a8d57127974b
- Affected versionversion=2f0c79dd1e9d55a279b0a8e363717b7a896fe7b4
- Affected versionversion=3.10.91 <3.11
- Affected versionversion=3.12.50 <3.13
- Affected versionversion=3.14.55 <3.15
- Affected versionversion=3.18.23 <3.19
- Affected versionversion=4.1.11 <4.2
- Affected versionversion=4.2
- Affected versionversion=4754957f04f5f368792a0eb7dab0ae89fb93dcfd <0160ac84fb03a0bd8dce8a42cb25bfaeedd110f4
- Affected versionversion=4754957f04f5f368792a0eb7dab0ae89fb93dcfd <7d0032112a0380d0b8d7c9005f621928a9b9fc76
- Affected versionversion=4754957f04f5f368792a0eb7dab0ae89fb93dcfd <a3a1b784791a3cbfc6e05c4d8a3c321ac5136e25
- Affected versionversion=4754957f04f5f368792a0eb7dab0ae89fb93dcfd <adbc8cc1162951cb152ed7f147d5fbd35ce3e62f
- Affected versionversion=4754957f04f5f368792a0eb7dab0ae89fb93dcfd <e34090d7214e0516eb8722aee295cb2507317c07
- Affected versionversion=cc2b6a186da7580d4557e7175c5ab4b18d9a57f0
- Affected versionversion=e89e653311ac2c9f37ceb778212ae4dbe1104091
- Affected versionversion=f1d62fb20245bc89d6ba93d829763450250a592b
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
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Technologies
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