CVE-2026-74556

CRITICALPre-NVD 9.89.8
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-15. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 19, 2026

Advisory Details (8)

Auto-updated Aug 19, 2026
No patch confirmed yet.
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f1a3a51fc5dba0e99532379665069f1700da6b44
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c97b5265cc47775f77fd2a23d6bde0426997b233
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c1dea15f819cded9b3faf58f8bec72323568b6e6
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a8f94cc9f0e5759252551be3a172960c57f21f54
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a51812842084fd390590ab8dc0431f10c73ddc56
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/72815741715bd41556dac5eeb068bf0f8af06ee7
generic

scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/084af0253673425ce2ae62e3c7f74f0dd023711b

Vendor Advisories for CVE-2026-74556(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 47× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-21 04:40 UTCGHSA enrichment
  2. 2026-08-21 00:17 UTCEG score recompute
  3. 2026-08-21 00:17 UTCGHSA enrichment
  4. 2026-08-20 22:56 UTCEPSS rescore
  5. 2026-08-20 19:56 UTCGHSA enrichment
  6. 2026-08-20 15:29 UTCGHSA enrichment
  7. 2026-08-20 11:06 UTCGHSA enrichment
  8. 2026-08-20 06:44 UTCGHSA enrichment
  9. 2026-08-20 02:22 UTCGHSA enrichment
  10. 2026-08-19 22:00 UTCGHSA enrichment
  11. 2026-08-19 17:38 UTCEG score recompute
  12. 2026-08-19 17:38 UTCGHSA enrichment
  13. 2026-08-19 17:04 UTCEPSS rescore
  14. 2026-08-19 16:52 UTCEG score recompute
  15. 2026-08-19 16:52 UTCGHSA enrichment
  16. 2026-08-19 15:20 UTCGHSA enrichment
  17. 2026-08-19 10:50 UTCGHSA enrichment
  18. 2026-08-19 06:28 UTCGHSA enrichment
  19. 2026-08-19 02:06 UTCGHSA enrichment
  20. 2026-08-18 21:44 UTCGHSA enrichment
  21. 2026-08-18 17:22 UTCEG score recompute
  22. 2026-08-18 17:22 UTCGHSA enrichment
  23. 2026-08-18 13:49 UTCEPSS rescore
  24. 2026-08-18 13:49 UTCEPSS rescore
  25. 2026-08-18 13:00 UTCGHSA enrichment
Show 22 more
  1. 2026-08-18 08:37 UTCGHSA enrichment
  2. 2026-08-18 04:13 UTCGHSA enrichment
  3. 2026-08-17 23:51 UTCGHSA enrichment
  4. 2026-08-17 19:29 UTCGHSA enrichment
  5. 2026-08-17 15:07 UTCEG score recompute
  6. 2026-08-17 15:07 UTCGHSA enrichment
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-17 10:45 UTCEG score recompute
  9. 2026-08-17 10:45 UTCGHSA enrichment
  10. 2026-08-17 06:23 UTCEG score recompute
  11. 2026-08-17 06:23 UTCGHSA enrichment
  12. 2026-08-17 05:54 UTCEG score recompute 9.80
  13. 2026-08-17 05:54 UTCGHSA enrichment
  14. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  15. 2026-08-17 05:39 UTCEG score recompute
  16. 2026-08-17 05:39 UTCGHSA enrichment
  17. 2026-08-17 05:39 UTCMITRE cvelistV5
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-15 13:27 UTCNVD update
  21. 2026-08-15 12:38 UTCEG score recompute
  22. 2026-08-15 12:37 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-74556?
CVE-2026-74556 is a critical vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer iscsitcphdr_dissect() receives the data segment of several PDU types into the fixed-size conn->data buffer, which is allocated for ISCSIDEFMAXRECVSEGLEN…
When was CVE-2026-74556 disclosed?
CVE-2026-74556 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74556 actively exploited?
CVE-2026-74556 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.7% of all scored CVEs.
What is the CVSS score of CVE-2026-74556?
CVE-2026-74556 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-74556?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74556, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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