Vulnerability in Linux kernel (CVE-2026-90110)
Summary
Vulnerability in Linux kernel (CVE-2026-90110). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
inetpeer: randomize RB-tree node comparison using SipHash
The inetpeer rate limiting system stores peer entries in a Red-Black tree
keyed deterministically on the remote IP address. Because tree lookups walk
the RB-tree using standard lexicographical comparisons (inetpeer_addr_cmp),
an off-path adversary can predict the exact topology of the tree and the
sequence of nodes traversed during lookups (the gc_stack candidate list).
By combining deterministic tree traversal with aggressive garbage collection
(triggered when tree size exceeds inet_peer_threshold), an attacker can
selectively force the eviction of targeted inet_peer nodes. When an evicted
node is subsequently re-created upon receiving a new packet, its rate-limiting
token bucket (rate_tokens, rate_last) is reset to full capacity. This creates
a side-channel primitive allowing off-path attackers to bypass IP-keyed ICMP
rate limits and infer open UDP ports (similar to SAD DNS style attacks).
Mitigate this by randomizing the RB-tree node comparison logic using SipHash
with a secret key (inetpeer_hash_key) initialized via net_get_random_once().
Nodes are ordered in the tree by SipHash(addr, key) rather than raw IP
addresses. Because the secret key is unknown to external entities, the tree
layout and lookup traversal paths are unpredictable to off-path adversaries,
breaking the deterministic eviction gadget.
Cache the computed 64-bit SipHash (hash) i…
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-2026-90110 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 9.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90110" on the vendor's site.
CVE-2026-90110 (Linux kernel) — CVSS v3 9.4
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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: Critical (CVSS 9.4/10). Confidential information can be exposed externally.
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-2026-90110 linux Fixed in: 6.1.190-1
- Ubuntu UBUNTU-CVE-2026-90110 linux-azure
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com