af_unix: Unify scc_index when finalising SCC in __unix_walk_scc().
In the Linux kernel, the following vulnerability has been resolved: af_unix: Unify scc_index when finalising SCC in __unix_walk_scc(). Commit bfdb01283ee8 ("af_unix: Assign a unique index to SCC.") changed Tarjan's algorithm to update lowlink with lowlink, which is called lowpoint (unix_vertex.scc_index). unix_vertex_dead() assumes all vertices in an SCC share the same lowpoint, but this is not always true if an SCC has two or more back edges, depending on the order of DFS. For example, the graph below has two back edges from B to A and from C to B. A --> B --> C ^ | ^ | `----' `----' If DFS walks through A -> B -> C -> B (-> C -> B) -> A (-> B -> A), each index and scc_index will be updated as follows. A --> B --> C C = (3, 3) (index, scc_index) B = (2, 2) A = (1, 1) A ... B ... C C = (3, 2)<-. ^ | B = (2, 2) -' `----' A = (1, 1) A ... B ... C C = (3, 2) ^ | . . B = (2, 1)<-. `----' .... A = (1, 1) -' Then, unix_vertex_dead() thinks that B is passed to another SCC with scc_index 2, and the SCC is not garbage-collected. This does not happen if DFS walks in a different order below or starts from B. 1 3 A --> B --> C ^ | ^ | `----' `----' 2 4 Let's unify scc_index across the SCC when finalising it. Note that updating v->index was previously done in unix_scc_dead(), when called from __unix_walk_scc(), just to save one loop. Since __unix_walk_scc() now iterates over the SCC anyway, the update is moved back to __unix_walk_scc() and 'fast' argument is dropped.
CVE-2026-98289
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98289
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4090fa373f0e763c43610853d2774b5979915959",
"lessThan": "b8f71d69380a5fbc734c868acbeb560f1de1766f",
"versionType": "git"
},
{
"status": "affected",
"version": "4090fa373f0e763c43610853d2774b5979915959",
"lessThan": "be550ee108ad80828aa61280400bedfc7e7c39d3",
"versionType": "git"
},
{
"status": "affected",
"version": "4090fa373f0e763c43610853d2774b5979915959",
"lessThan": "4a4263dfeabad72f95e8ab6e15146861fa4144dd",
"versionType": "git"
},
{
"status": "affected",
"version": "5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a",
"versionType": "git"
},
{
"status": "affected",
"version": "de7921631ff323369aa63a4324695ab54ea4047e",
"versionType": "git"
},
{
"status": "affected",
"version": "6.1.141",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.93",
"lessThan": "6.7",
"versionType": "semver"
}
],
"programFiles": [
"net/unix/garbage.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.54",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.8",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/unix/garbage.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98289
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38367 · Revision 1
- Added to Heist Feed
- Publisher date