CVE-2026-98555

llc: fix skb UAF and leaks on llc_mac_hdr_init() failure

CVE-2026-98555 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-98555, released October 19, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.5

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0031

23rd percentile

In the Linux kernel, the following vulnerability has been resolved: llc: fix skb UAF and leaks on llc_mac_hdr_init() failure In llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(), if llc_mac_hdr_init() fails, kfree_skb(skb) is called instead of kfree_skb(nskb). This leaks the newly allocated nskb, reads from the freed skb via LLC_I_GET_NR(pdu), and double-frees skb when llc_conn_state_process() drops its reference. In llc_sap_action_send_xid_r() and llc_sap_action_send_test_r(), nskb is leaked if llc_mac_hdr_init() returns an error. Free nskb in all three error paths.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
linux · Debian 12.15 (bookworm)	6.1.190-1	DEBIAN-CVE-2026-98555	Oct 19, 2026
linux · Debian 13.5 (trixie)	6.12.113-1	DEBIAN-CVE-2026-98555	Oct 19, 2026
linux · Debian 14	7.2.9-1	DEBIAN-CVE-2026-98555	Oct 19, 2026
linux-6.12 · Debian 12.15 (bookworm)	6.12.113-1~deb12u1	DEBIAN-CVE-2026-98555	Oct 19, 2026

Details

Published
October 18, 2026
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98555

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