CVE-2026-98582

Description

In the Linux kernel, the following vulnerability has been resolved: nfc: st21nfca: validate received frame size st21nfca_hci_i2c_repack() trims a received frame at its EOF marker before removing byte stuffing. It then assumes the truncated frame contains the LLC header and two CRC bytes, and it unconditionally reads the byte after an escape marker. A malformed frame can place EOF immediately after the start marker or can end its data portion with an escape marker. The former leaves too few bytes for check_crc(), while the latter makes the unstuffing loop read past the current skb length. Require the minimum framing bytes both before and after unstuffing. Use separate input and output cursors while removing byte stuffing, and reject an escape marker without its encoded byte. This keeps malformed frames within the received frame boundary before CRC processing.

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EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/57919d0662d8856211b794140172e51ca389f23d https://git.kernel.org/stable/c/7b996cc06dda54c02a5aa607bda01109f0ac51e6 https://git.kernel.org/stable/c/8934d2889ae16a7c77520e002398d0689c1ecea5 https://git.kernel.org/stable/c/91be5161f37b0a2795ad6806d69be5fa74522e5c https://git.kernel.org/stable/c/a653c01ce447f10c36b901646888c0330363af4f https://git.kernel.org/stable/c/d0596ee6c4b928a5c288790522a7495ee867da72 https://git.kernel.org/stable/c/d4008c3499dba7829bfe002edd99a8bff8ae3a7c https://git.kernel.org/stable/c/f526c218a149a30f110ce434ff17e033042404b8

Frequently Asked Questions

What is CVE-2026-98582? +

In the Linux kernel, the following vulnerability has been resolved: nfc: st21nfca: validate received frame size st21nfca_hci_i2c_repack() trims a received frame at its EOF marker before removing byte stuffing. It then assumes the truncated frame contains the LLC header and two CRC bytes, and it unconditionally reads the byte after an escape marker. A malformed frame can place EOF immediately after the start marker or can end its data portion with an escape marker. The former leaves too few bytes for check_crc(), while the latter makes the unstuffing loop read past the current skb length. Require the minimum framing bytes both before and after unstuffing. Use separate input and output cursors while removing byte stuffing, and reject an escape marker without its encoded byte. This keeps malformed frames within the received frame boundary before CRC processing.

How do I check if I'm vulnerable to CVE-2026-98582? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.