CVE-2026-98123

CVE CVE-2026-98123EUVD EUVD-2026-86954Veröffentlicht 2026-09-25T10:36:05.000Z

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration sctp_verify_asconf() walks ASCONF-ACK parameters with sctp_walk_params(), which advances by SCTP_PAD4(length), while the consumer sctp_get_asconf_response() iterates the same parameters advancing by the raw length, without padding. A single odd-length parameter desynchronises the two walks and makes the consumer interpret attacker-controlled bytes at a misaligned offset. When those bytes yield a length of zero, the while loop over asconf_ack_len makes no progress, spinning forever in softirq context, and the watchdog reports a soft lockup. All reads stay within the received skb, so the lockup is a pure remote denial of service. A remote peer can trigger it with a crafted ASCONF-ACK on an ADD-IP enabled association with an outstanding ASCONF (RFC 5061 section 4.1.2 requires the chunk to be authenticated, but the predefined empty key id 0 allows the peer to compute the same association HMAC from publicly exchanged parameters, so the gate does not help). The SCTP_PARAM_ERR_CAUSE case of sctp_verify_asconf() also performs no length check, letting a parameter without a complete error header reach the consumer, which reads errhdr.cause past the end of the parameter, an out-of-bounds read. Reject SCTP_PARAM_ERR_CAUSE parameters shorter than sizeof(struct sctp_addip_param) + sizeof(struct sctp_errhdr) at the verifier, and advance the consumer iterator with the same padding rule as the verifier to keep the two walks in lockstep. The verifier change guarantees a complete error header in every ERR_CAUSE parameter the consumer can see, so the consumer's asconf_ack_len check is dropped and it returns err_param->cause directly. The consumer padding fix is still required because odd lengths remain valid for SCTP_PARAM_ERR_CAUSE per RFC 5061. The issue was found by ZeroHive, a vulnerability hunting agent at Tencent Yunding Lab.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux 2.6.12; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7ba84e2971d208a2d6413a334ec28a8a32cdce0f; patch: 6.12.111; patch: 7.2.7; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <abf59d7f6fff23227256e8199aca5ade45758f8b; patch: 6.18.53; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3be02999ab9131a4b96eb1eda4ca48b1cea80f03; patch: 7.3-rc2; patch: 0; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2cb0b0b1ed69430bf73740377ea0a1c44c50db63

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

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• Linux — Linux

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