net/sched: fix potential stack infoleak in em_text_dump()
In the Linux kernel, the following vulnerability has been resolved: net/sched: fix potential stack infoleak in em_text_dump() em_text_dump() allocates struct tcf_em_text on the stack without zeroing it. strscpy() writes the algorithm name and a NUL terminator into conf.algo[], leaving the remaining bytes uninitialised. nla_put_nohdr() then copies the full struct to the netlink response. KMSAN on Linux 7.2-rc6 reports two kernel-infoleak splats from this path, one triggered via "tc filter show" and one via a raw RTM_GETTFILTER dump: BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x1c9/0x2620 nla_put_nohdr+0x83/0x130 em_text_dump+0x291/0x550 Local variable conf created at: em_text_dump+0x5d/0x550 Bytes 168-179 of 199 are uninitialized I am not certain whether this constitutes a real security problem in practice: the test was conducted in a controlled KMSAN environment and the leaked stack bytes may or may not carry sensitive data on actual production kernels. I am reporting it because KMSAN flagged it as a kernel-infoleak and the fix is straightforward. I can provide a userspace reproducer on request. The original code used strncpy() which zero-pads to the destination size. Commit b04202d6065c ("net/sched: replace strncpy with strscpy") replaced it with strscpy(), which does not pad, creating this condition. Zero-initialising the struct closes it.
CVE-2026-98584
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-2026-98584
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": "b04202d6065cba5dfd51fb9866400b25573eac67",
"lessThan": "9923e1c537f91f3530b52d4efce85f3d9c131bf8",
"versionType": "git"
},
{
"status": "affected",
"version": "b04202d6065cba5dfd51fb9866400b25573eac67",
"lessThan": "0b160417826d22f24fc31a5b9cfae3b14aa70f76",
"versionType": "git"
},
{
"status": "affected",
"version": "b04202d6065cba5dfd51fb9866400b25573eac67",
"lessThan": "9c572a83037a7dcd653ba3a9cc468c16b857d0c9",
"versionType": "git"
}
],
"programFiles": [
"net/sched/em_text.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.17"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.17",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/em_text.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98584
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38602 · Revision 1
- Added to Heist Feed
- Publisher date