CVE-2026-89541

CVE CVE-2026-89541EUVD EUVD-2026-76452Veröffentlicht 2026-09-11T19:44:18.000ZZuletzt geändert 2026-09-14T12:00:48.000ZCVSS 9.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: harden gss_unwrap_resp_priv length checks gss_unwrap_resp_priv() validates the RPCSEC_GSS opaque length with offset = (u8 *)(p) - (u8 *)head->iov_base; if (offset + opaque_len > rcv_buf->len) goto unwrap_failed; maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, offset + opaque_len, rcv_buf); Both operands are u32 and the sum is computed in u32. A reply with opaque_len near 0xffffffff makes offset + opaque_len wrap to a small value that is below rcv_buf->len, so the bound check passes and gss_unwrap() is called with end < begin. The check also lacks a lower bound, so any opaque_len in [0, GSS_KRB5_TOK_HDR_LEN) is accepted and forwarded to gss_krb5_unwrap_v2(), whose pre-decrypt header reads at ptr+4 and ptr+6 then run past the token. A krb5p NFS server returning a crafted RPCSEC_GSS reply can drive the client into out-of-bounds reads in gss_krb5_unwrap_v2() and the rotate_left() loop that follows. Fix by replacing the single combined check with three guards that are safe in u32 arithmetic and that enforce the RFC 4121 minimum outer token length: if (offset > rcv_buf->len) goto unwrap_failed; if (opaque_len > rcv_buf->len - offset) goto unwrap_failed; if (opaque_len < GSS_KRB5_TOK_HDR_LEN) goto unwrap_failed; The first guard makes the subtraction in the second guard unconditionally safe; offset is derived from a successful xdr_inline_decode() in the head kvec, so in practice it already satisfies the bound. The floor mirrors the server-side check added in commit 5b757c2e57a5 ("SUNRPC: svcauth_gss: enforce krb5 token minimum length").

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 patch: 6.1.188; patch: 5.15.221; patch: 0; 2.6.15; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <ebcbd2523a8524c3d24e111cdbed8e271d910269; patch: 6.12.109; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <89a15a50f84d32d4b99db86f957427fcbe20a99a; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <87831b92112c81db251d46756d65daa4f91af6a2; patch: 6.6.157; patch: 7.3-rc1; patch: 5.10.270; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <81fd7654a8429718adfcb2a7e03496077f547ed0; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <d395c30d570ca6168f0297b191709927d1258273; patch: 6.18.50; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <3691c4b3488d8ca046b9941e5be30c626dbbbb50; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <85fa6b12e8f439739ac36ef2aad925f37c8b976a; patch: 7.2.4; 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf <401f6a5b338d05bb1069ad814d9f77e3c367854f

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.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.