VulnerabilityPublished 18 Oct 2026

CVE-2026-98584: Linux kernel · net/sched: fix potential stack infoleak in em_text_dump()

Source GCVE Database

Authoritative record:CVE-2026-98584· Low

Not known to be exploited · fixed in 9923e1c537f91f3530b52d4efce85f3d9c131bf8 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Low

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 9923e1c537f91f3530b52d4efce85f3d9c131bf8, 9c572a83037a7dcd653ba3a9cc468c16b857d0c9, 0b160417826d22f24fc31a5b9cfae3b14aa70f76

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-r555-rgvq-cqv7

What to do

Upgrade Linux kernel to 9923e1c537f91f3530b52d4efce85f3d9c131bf8, 9c572a83037a7dcd653ba3a9cc468c16b857d0c9 or 0b160417826d22f24fc31a5b9cfae3b14aa70f76.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ b04202d6065cba5dfd51fb9866400b25573eac67, < 9923e1c537f91f3530b52d4efce85f3d9c131bf8	Fixed in 9923e1c537f91f3530b52d4efce85f3d9c131bf8
LinuxLinux	Affected ≥ b04202d6065cba5dfd51fb9866400b25573eac67, < 9c572a83037a7dcd653ba3a9cc468c16b857d0c9	Fixed in 9c572a83037a7dcd653ba3a9cc468c16b857d0c9
LinuxLinux	Affected ≥ b04202d6065cba5dfd51fb9866400b25573eac67, < 0b160417826d22f24fc31a5b9cfae3b14aa70f76	Fixed in 0b160417826d22f24fc31a5b9cfae3b14aa70f76
LinuxLinux	Affected =6.17	Fixed in–

AI-suggested

A fix is available that zero-initializes the struct tcf_em_text in em_text_dump() before use, preventing uninitialized data from being leaked. Users should apply the official Linux kernel patch that addresses this issue. Since this is a kernel code fix, upgrading to a kernel version including this patch is the recommended remediation.

Description

A potential stack information leak vulnerability in the Linux kernel's net/sched subsystem was identified and resolved. The issue involved the em_text_dump() function allocating a struct on the stack without zero-initializing it, leading to uninitialized bytes being copied into netlink responses. This was detected by KMSAN during testing but its practical security impact is uncertain. The vulnerability arose after replacing strncpy() with strscpy(), which does not zero-pad the destination buffer. The fix involves zero-initializing the struct to prevent leakage.

Impact

The vulnerability could lead to leakage of uninitialized stack memory contents in netlink responses, potentially exposing sensitive kernel stack data. However, the reporter notes uncertainty about whether this results in a real security problem in production environments, as the leak was observed in a controlled KMSAN environment. No known exploits in the wild have been reported.

Summary

The Linux kernel net/sched subsystem had a potential stack infoleak in the em_text_dump() function. The function allocated a struct tcf_em_text on the stack without zeroing it, and strscpy() wrote the algorithm name and a NUL terminator into a field, leaving the rest uninitialized. This uninitialized data was then copied in full to netlink responses via nla_put_nohdr(). KMSAN testing on Linux 7.2-rc6 flagged kernel-infoleak warnings triggered by commands like "tc filter show" and raw RTM_GETTFILTER dumps. The issue originated from a code change replacing strncpy() (which zero-pads) with strscpy() (which does not), causing the uninitialized bytes to be exposed. The vulnerability was fixed by zero-initializing the struct before use.

References

Community reviews

Loading reviews…