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CVE-2026-89538: Linux

9.8

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

  • Експлоатация: няма данни за експлоатация
  • Атаката може да се автоматизира

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field gss_krb5_unwrap_v2() sets buf->len to a logical length, which can be much smaller than head[0].iov_len (the allocated receive-page capacity). It then calls xdr_buf_trim() with a trim length derived from the 16-bit "extra count" (ec) field in the Kerberos v2 token header. The ec field is authenticated by the post-decrypt memcmp() against the encrypted header copy, so a randomly-mutated value is rejected. However, any peer holding a valid GSS context can legitimately encrypt a token whose ec exceeds the plaintext length. Per RFC 4121, such a token is structurally malformed. Although xdr_buf_trim() now clamps the buf->len subtraction to avoid unsigned underflow, the buffer is still left in a semantically invalid state (zero length, inconsistent iov lengths) when ec is oversized. Reject these tokens before calling xdr_buf_trim(), giving callers a well-defined GSS_S_DEFECTIVE_TOKEN error and keeping the xdr_buf internally consistent. The wrapped blob begins at a nonzero offset -- both callers pass len as offset + opaque_len -- so buf->len still counts the offset bytes that precede the blob. Compare the trim length against the remaining wrapped segment, buf->len - offset, rather than the whole buffer; comparing against buf->len alone leaves an offset-wide window in which an oversized ec passes the test and xdr_buf_trim() cuts into the bytes ahead of the blob.

Засегнати продукти

  • Linux Linux: cf4c024b908353fcc48309374d39e3399d67dfd1 преди ac9efc29346b6942e71f0e24a3178a9121330fab; cf4c024b908353fcc48309374d39e3399d67dfd1 преди b5746095b59f4d11f39f08751d36bbdfd1e5deac; cf4c024b908353fcc48309374d39e3399d67dfd1 преди 9fc6d6e6db49ab55208d5dd1c424c1d0d9aa7296; cf4c024b908353fcc48309374d39e3399d67dfd1 преди 4abb44a29bb515df6f49123848765c70fc9b5021; cf4c024b908353fcc48309374d39e3399d67dfd1 преди dfcd81ab45613d45996fbf483d4ef54b0ec90ab9; cf4c024b908353fcc48309374d39e3399d67dfd1 преди 1f9856af065b6158271687e9788407b9573fd16f; cf4c024b908353fcc48309374d39e3399d67dfd1 преди 880effc943ed82d6811f272ed3307c222b40f4d6; cf4c024b908353fcc48309374d39e3399d67dfd1 преди ad484748eec0a66eac0f13ab53b3fbedb7333c91
  • Linux Linux: 3.13; преди 3.13; 5.10.270 до 5.10.*; 5.15.221 до 5.15.*; 6.1.188 до 6.1.*; 6.6.157 до 6.6.*; 6.12.109 до 6.12.*; 6.18.50 до 6.18.*; 7.2.4 до 7.2.*; от 7.3 нататък

История

  • 11 септември 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-89538: Linux | freedomonline.bg