CVE-2026-74556

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM 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 — 4 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: 0.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.8CRITICALmedium confidence
EG Risk
49
EG Risk 49/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
31st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 15, 2026

Last Modified

August 19, 2026

Advisory Details (8)

Auto-updated Sep 30, 2026
Patch available.
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

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1035.38) @ noble2026-10-05ubuntu
redhatkernel-rt-0:4.18.0-553.163.1.rt7.504.el8_102026-09-15redhat
redhatkernel-0:4.18.0-553.163.1.el8_102026-09-15redhat
redhatkernel-0:5.14.0-687.48.1.el9_82026-09-15redhat
redhatkernel-0:6.12.0-211.55.1.el10_22026-09-15redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (56 versions)
  • every version up to 6.1.187-1: fixed in 6.1.187-1
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1
  • every version up to 6.12.107-1~deb12u1: fixed in 6.12.107-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (33 versions)
  • every version up to 6.12.105-1: fixed in 6.12.105-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (165 versions)
  • every version up to 7.1.8-1: fixed in 7.1.8-1
—

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 55× in last 7d / 272× 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.

Showing the most recent 100 of 426 total refreshes for this CVE.

  1. 2026-10-05 12:02 UTCVendor advisory
  2. 2026-10-05 12:02 UTCGHSA enrichment
  3. 2026-10-05 06:45 UTCVendor advisory
  4. 2026-10-05 06:45 UTCGHSA enrichment
  5. 2026-10-05 02:23 UTCEG score recompute
  6. 2026-10-05 02:23 UTCVendor advisory
  7. 2026-10-05 02:23 UTCGHSA enrichment
  8. 2026-10-04 23:22 UTCEPSS rescore
  9. 2026-10-04 21:54 UTCVendor advisory
  10. 2026-10-04 21:54 UTCGHSA enrichment
  11. 2026-10-04 16:32 UTCVendor advisory
  12. 2026-10-04 16:32 UTCGHSA enrichment
  13. 2026-10-04 12:09 UTCVendor advisory
  14. 2026-10-04 12:09 UTCGHSA enrichment
  15. 2026-10-04 07:46 UTCVendor advisory
  16. 2026-10-04 07:46 UTCGHSA enrichment
  17. 2026-10-04 03:24 UTCVendor advisory
  18. 2026-10-04 03:24 UTCGHSA enrichment
  19. 2026-10-03 19:28 UTCEG score recompute
  20. 2026-10-03 19:28 UTCVendor advisory
  21. 2026-10-03 19:28 UTCGHSA enrichment
  22. 2026-10-03 14:26 UTCEPSS rescore
  23. 2026-10-03 02:08 UTCVendor advisory
  24. 2026-10-03 02:08 UTCGHSA enrichment
  25. 2026-10-02 21:45 UTCEG score recompute
Show 75 more
  1. 2026-10-02 21:45 UTCVendor advisory
  2. 2026-10-02 21:45 UTCGHSA enrichment
  3. 2026-10-02 15:50 UTCVendor advisory
  4. 2026-10-02 15:49 UTCGHSA enrichment
  5. 2026-10-02 07:02 UTCVendor advisory
  6. 2026-10-02 07:02 UTCGHSA enrichment
  7. 2026-10-02 01:59 UTCEG score recompute
  8. 2026-10-02 01:59 UTCVendor advisory
  9. 2026-10-02 01:59 UTCGHSA enrichment
  10. 2026-10-01 19:50 UTCEPSS rescore
  11. 2026-10-01 14:38 UTCVendor advisory
  12. 2026-10-01 14:38 UTCGHSA enrichment
  13. 2026-10-01 10:16 UTCVendor advisory
  14. 2026-10-01 10:16 UTCGHSA enrichment
  15. 2026-10-01 05:54 UTCVendor advisory
  16. 2026-10-01 05:54 UTCGHSA enrichment
  17. 2026-10-01 01:33 UTCVendor advisory
  18. 2026-10-01 01:33 UTCGHSA enrichment
  19. 2026-09-30 20:55 UTCEG score recompute
  20. 2026-09-30 20:55 UTCVendor advisory
  21. 2026-09-30 20:55 UTCGHSA enrichment
  22. 2026-09-29 15:24 UTCEPSS rescore
  23. 2026-09-29 08:26 UTCVendor advisory
  24. 2026-09-29 08:26 UTCGHSA enrichment
  25. 2026-09-29 04:04 UTCVendor advisory
  26. 2026-09-29 04:04 UTCGHSA enrichment
  27. 2026-09-28 23:35 UTCEG score recompute
  28. 2026-09-28 23:35 UTCVendor advisory
  29. 2026-09-28 23:35 UTCGHSA enrichment
  30. 2026-09-28 13:52 UTCEPSS rescore
  31. 2026-09-28 11:55 UTCVendor advisory
  32. 2026-09-28 11:55 UTCGHSA enrichment
  33. 2026-09-28 07:28 UTCVendor advisory
  34. 2026-09-28 07:28 UTCGHSA enrichment
  35. 2026-09-28 03:06 UTCVendor advisory
  36. 2026-09-28 03:06 UTCGHSA enrichment
  37. 2026-09-27 22:32 UTCVendor advisory
  38. 2026-09-27 22:32 UTCGHSA enrichment
  39. 2026-09-27 17:08 UTCEG score recompute
  40. 2026-09-27 17:08 UTCVendor advisory
  41. 2026-09-27 17:08 UTCGHSA enrichment
  42. 2026-09-27 13:48 UTCEPSS rescore
  43. 2026-09-27 12:45 UTCVendor advisory
  44. 2026-09-27 12:45 UTCGHSA enrichment
  45. 2026-09-27 08:23 UTCEG score recompute
  46. 2026-09-27 08:23 UTCVendor advisory
  47. 2026-09-27 08:23 UTCGHSA enrichment
  48. 2026-09-26 15:59 UTCEPSS rescore
  49. 2026-09-26 00:28 UTCEPSS rescore
  50. 2026-09-25 11:52 UTCVendor advisory
  51. 2026-09-25 11:52 UTCGHSA enrichment
  52. 2026-09-25 06:47 UTCVendor advisory
  53. 2026-09-25 06:47 UTCGHSA enrichment
  54. 2026-09-25 02:25 UTCVendor advisory
  55. 2026-09-25 02:25 UTCGHSA enrichment
  56. 2026-09-24 16:23 UTCEG score recompute
  57. 2026-09-24 16:23 UTCVendor advisory
  58. 2026-09-24 16:23 UTCGHSA enrichment
  59. 2026-09-24 14:04 UTCEPSS rescore
  60. 2026-09-24 09:40 UTCVendor advisory
  61. 2026-09-24 09:40 UTCGHSA enrichment
  62. 2026-09-24 05:18 UTCVendor advisory
  63. 2026-09-24 05:18 UTCGHSA enrichment
  64. 2026-09-24 00:53 UTCVendor advisory
  65. 2026-09-24 00:53 UTCGHSA enrichment
  66. 2026-09-23 20:31 UTCEG score recompute
  67. 2026-09-23 20:31 UTCVendor advisory
  68. 2026-09-23 20:31 UTCGHSA enrichment
  69. 2026-09-23 17:54 UTCEPSS rescore
  70. 2026-09-23 14:15 UTCVendor advisory
  71. 2026-09-23 14:14 UTCGHSA enrichment
  72. 2026-09-23 09:52 UTCVendor advisory
  73. 2026-09-23 09:52 UTCGHSA enrichment
  74. 2026-09-23 05:30 UTCVendor advisory
  75. 2026-09-23 05:30 UTCGHSA enrichment

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 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 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74556?
CVE-2026-74556 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-74556?
A fix for CVE-2026-74556 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-74556 are linked in the Vendor Advisories panel on this page.

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