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CVE-2026-74556

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.4%
Linux•Linux•Versions : <=6.1.*, <2.6.29, <=6.12.*, <c1dea15f819cded9b3faf58f8bec72323568b6e6, 0, <=7.1.*, <b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676, 5.15.216, <c97b5265cc47775f77fd2a23d6bde0426997b233, 6.12.103, <084af0253673425ce2ae62e3c7f74f0dd023711b, 2.6.29, <=5.10.*, <=6.6.*, <a51812842084fd390590ab8dc0431f10c73ddc56, 6.1.183, <f1a3a51fc5dba0e99532379665069f1700da6b44, <72815741715bd41556dac5eeb068bf0f8af06ee7, <=6.18.*, a081c13e39b5c17052a7b46fafa61019c4c110ff, <=*, <=5.15.*, 7.1.8, <a8f94cc9f0e5759252551be3a172960c57f21f54, 6.18.44, 6.6.151, 5.10.265, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer iscsi_tcp_hdr_dissect() receives the data segment of several PDU types into the fixed-size conn->data buffer, which is allocated for ISCSI_DEF_MAX_RECV_SEG_LEN (8192) bytes. For the LOGIN_RSP, TEXT_RSP, REJECT and ASYNC_EVENT opcodes the dissect path already rejects a PDU whose DataSegmentLength exceeds that buffer. The SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) path also copies its data segment (sense/response data) into conn->data via iscsi_tcp_data_recv_prep(), but it does so without the same check. The only upstream bound on in.datalen is conn->max_recv_dlength, the initiator's advertised MaxRecvDataSegmentLength, which is commonly negotiated well above 8192 (open-iscsi defaults to 262144). A target that returns a SCSI Response with a DataSegmentLength between 8193 and max_recv_dlength therefore overflows the 8192-byte conn->data buffer. Once the same bound applies, ISCSI_OP_SCSI_CMD_RSP is handled exactly like those responses: bound the data segment, receive it into conn->data when present, and otherwise complete the PDU with no data. Fold the opcode into that case group rather than duplicating the check.

Gravité et risque d'exploitation

CVE-2026-74556 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.40 %, ce qui la place devant 32.7 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <2.6.29, <=6.12.*, <c1dea15f819cded9b3faf58f8bec72323568b6e6, 0, <=7.1.*, <b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676, 5.15.216, <c97b5265cc47775f77fd2a23d6bde0426997b233, 6.12.103, <084af0253673425ce2ae62e3c7f74f0dd023711b, 2.6.29, <=5.10.*, <=6.6.*, <a51812842084fd390590ab8dc0431f10c73ddc56, 6.1.183, <f1a3a51fc5dba0e99532379665069f1700da6b44, <72815741715bd41556dac5eeb068bf0f8af06ee7, <=6.18.*, a081c13e39b5c17052a7b46fafa61019c4c110ff, <=*, <=5.15.*, 7.1.8, <a8f94cc9f0e5759252551be3a172960c57f21f54, 6.18.44, 6.6.151, 5.10.265, 7.2) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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