Vulnerability in Linux kernel (CVE-2026-98595)
Summary
Vulnerability in Linux kernel (CVE-2026-98595). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
udp: remove a disconnected socket from the 4-tuple hash table
A UDP socket bound to a specific address and port keeps its entry in the
4-tuple hash table after it is disconnected:
sk binds to 127.0.0.1:21001
sk connects to 127.0.0.2:20001 // filed in the 4-tuple table
sk disconnects, connect(AF_UNSPEC) // still filed, peer now 0.0.0.0:0
__udp_disconnect() takes a socket out of that table only as a side effect
of ->rehash() or ->unhash(), and it skips ->rehash() when
SOCK_BINDADDR_LOCK is set and ->unhash() when SOCK_BINDPORT_LOCK is set.
commit 6996a2d2d0a6 ("udp: Unhash auto-bound connected sk from 4-tuple hash
table when disconnected.") fixed the same end state for a wildcard-bound
socket, by a path this one does not take.
The entry is counted whether or not anything hits it. hash4_cnt on the
hash2 slot stays raised for as long as the socket lives, so udp_has_hash4()
keeps sending every packet for that address and port through the 4-tuple
lookup first.
On IPv6 it can also be hit. __udp_disconnect() does not clear sk_v6_daddr,
so udp_v6_rehash() files the entry under the peer the socket was connected
to with a zero dport, and inet6_match() compares that same
field: a datagram from the former peer with a zero source port matches,
and source port zero is accepted on receive. On IPv4 the peer is cleared,
so a match would need a zero source address as well, which the routing
layer rejects as ma…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-98595 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98595" on the vendor's site.
CVE-2026-98595 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-98595 linux Fixed in: 7.2.9-1
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com