VulnerabilityPublished 18 Oct 2026

CVE-2026-98582: Linux kernel · nfc: st21nfca: validate received frame size

Source GCVE Database

Authoritative record:CVE-2026-98582· Medium

Not known to be exploited · fixed in f526c218a149a30f110ce434ff17e033042404b8 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f526c218a149a30f110ce434ff17e033042404b8, d4008c3499dba7829bfe002edd99a8bff8ae3a7c, d0596ee6c4b928a5c288790522a7495ee867da72 +5

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-g367-xhx5-qhm5

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < f526c218a149a30f110ce434ff17e033042404b8	Fixed in f526c218a149a30f110ce434ff17e033042404b8
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < d4008c3499dba7829bfe002edd99a8bff8ae3a7c	Fixed in d4008c3499dba7829bfe002edd99a8bff8ae3a7c
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < d0596ee6c4b928a5c288790522a7495ee867da72	Fixed in d0596ee6c4b928a5c288790522a7495ee867da72
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < a653c01ce447f10c36b901646888c0330363af4f	Fixed in a653c01ce447f10c36b901646888c0330363af4f
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < 57919d0662d8856211b794140172e51ca389f23d	Fixed in 57919d0662d8856211b794140172e51ca389f23d
LinuxLinux	Affected ≥ 3096e25a3e40b73afd59e46f3bf8d84f919992a1, < 8934d2889ae16a7c77520e002398d0689c1ecea5	Fixed in 8934d2889ae16a7c77520e002398d0689c1ecea5

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AI-suggested

A fix has been implemented in the Linux kernel NFC driver to validate frame sizes properly and safely handle byte unstuffing. Users should apply the official kernel updates that include this patch to remediate the vulnerability.

Description

A vulnerability in the Linux kernel's NFC driver for the ST21NFCA chip was resolved. The function st21nfca_hci_i2c_repack() improperly handles received frames by trimming at the EOF marker before removing byte stuffing, leading to unsafe assumptions about frame contents. Malformed frames can cause the function to read beyond buffer boundaries, potentially leading to memory corruption. The fix enforces minimum framing byte requirements and corrects the byte unstuffing logic to reject malformed frames.

Impact

Malformed NFC frames can cause the vulnerable function to read beyond the allocated buffer, potentially leading to memory corruption. This could affect kernel stability or security depending on how the corrupted memory is used. No known exploits are reported in the wild.

Summary

The Linux kernel NFC driver for the ST21NFCA chip contained a vulnerability in the st21nfca_hci_i2c_repack() function. This function trims a received frame at its EOF marker before removing byte stuffing and assumes the truncated frame contains the LLC header and two CRC bytes. It unconditionally reads the byte after an escape marker, which can lead to out-of-bounds reads if a malformed frame places EOF immediately after the start marker or ends with an escape marker. The fix requires minimum framing bytes before and after unstuffing, uses separate cursors for input and output during byte unstuffing, and rejects escape markers without their encoded byte, preventing malformed frames from causing buffer overreads during CRC processing.

References

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