inetpeer: randomize RB-tree node comparison using SipHash

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90110
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:02 UTC
Updated2026-09-18 18:17:42 UTC
DescriptionIn 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) in struct inet_peer and compute the target hash (dhash) once at the beginning of inet_getpeer() to avoid recomputing SipHash at every step of the RB-tree walk.

Risk And Classification

Primary CVSS: v3.1 9.4 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

EPSS: 0.005950000 probability, percentile 0.468370000 (date 2026-09-21)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
3.1CNADECLARED9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 b20e98f0bb668a59abaf7bcf85d75c073e90d352 git Not specified
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 5f127e3cc9647a8a70db12c65dbd0de473545380 git Not specified
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 199fcf285e498111e029137d088949bc6c26d578 git Not specified
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 857681f6835d5b0a7bc4a34a026baeaaf5215623 git Not specified
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 7109bb63667a53e4542ad845476f97d0c8b28a61 git Not specified
CNA Linux Linux affected b145425f269a17ed344d737f746b844dfac60c82 2ee66e9487172fcd189bc52a767c30dad7141c09 git Not specified
CNA Linux Linux affected 4.14 Not specified
CNA Linux Linux unaffected 4.14 semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/5f127e3cc9647a8a70db12c65dbd0de473545380 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2ee66e9487172fcd189bc52a767c30dad7141c09 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7109bb63667a53e4542ad845476f97d0c8b28a61 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/199fcf285e498111e029137d088949bc6c26d578 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/857681f6835d5b0a7bc4a34a026baeaaf5215623 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b20e98f0bb668a59abaf7bcf85d75c073e90d352 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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