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CVE-2026-63886: Linux, грешка в паметта

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.

CVE радар: още уязвимости от този вид

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

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Validate CHAP_R length before base64 decode chap_server_compute_hash() allocates client_digest as kzalloc(chap->digest_size) and then, for BASE64-encoded responses, passes chap_r directly to chap_base64_decode() without checking whether the input length could produce more than digest_size bytes of output. chap_base64_decode() writes to the destination unconditionally as long as there is input to consume. With MAX_RESPONSE_LENGTH set to 128 and the "0b" prefix stripped by extract_param(), up to 127 base64 characters can reach the decoder. 127 characters decode to 95 bytes. For SHA-256 (digest_size=32) this overflows client_digest by 63 bytes; for MD5 (digest_size=16) the overflow is 79 bytes. The length check at line 344 fires after the write has already happened. The HEX branch in the same switch statement already validates the length up front. Apply the same approach to the BASE64 branch: strip trailing base64 padding characters, then reject any input whose data length exceeds DIV_ROUND_UP(digest_size * 4, 3) before calling the decoder. Stripping trailing '=' before the comparison handles both padded and unpadded encodings. chap_base64_decode() already returns early on '=', so the full original string is still passed to the decoder unchanged. The mutual CHAP path decodes CHAP_C into initiatorchg_binhex, which is kzalloc(CHAP_CHALLENGE_STR_LEN). extract_param() caps initiatorchg at CHAP_CHALLENGE_STR_LEN characters, so at most CHAP_CHALLENGE_STR_LEN-1 base64 characters reach the decoder. The maximum decoded size, DIV_ROUND_UP((CHAP_CHALLENGE_STR_LEN-1) * 3, 4), is less than CHAP_CHALLENGE_STR_LEN, so no overflow is possible there. A comment is added at the call site to document this.

Засегнати продукти

  • Linux Linux: 1e5733883421495908f3b90d9d807663038b4136 преди 82454e6f21e56ea9a0a9de7d0ff7e1dfb83e34d6; 1e5733883421495908f3b90d9d807663038b4136 преди edd06675a02376ea8347dba7c29ad982ba5b36ee; 1e5733883421495908f3b90d9d807663038b4136 преди bf154c657828ed05399bca5d98cf1611bb048b12; 1e5733883421495908f3b90d9d807663038b4136 преди 4a3a19c98a8207ad08bec554703d90f2c34a8cc6; 1e5733883421495908f3b90d9d807663038b4136 преди c04e85799356120209b351a148ac2db888d5ffd9; 1e5733883421495908f3b90d9d807663038b4136 преди 85db7391310b1304d2dc8ae3b0b12105a9567147
  • Linux Linux: 6.0; преди 6.0; 6.1.176 до 6.1.*; 6.6.143 до 6.6.*; 6.12.93 до 6.12.*; 6.18.35 до 6.18.*; 7.0.12 до 7.0.*; от 7.1 нататък

Вид слабост

История

  • 19 юли 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-63886: Linux, грешка в паметта | freedomonline.bg