CVE-2026-65653

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (51st percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
8.7EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 8.7Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

github.com/temporalio/tchannel-go did not reject TChannel call fragments containing checksum metadata but no length-prefixed argument chunks. The fragment reader left its chunk slice empty and then unconditionally selected the first element. A network peer can supply such a malformed call fragment, including as a direct initial call request after completing the standard initialization handshake. On that inbound path, the resulting unrecovered Go slice-bounds panic occurs on a library-created dispatch goroutine and terminates the hosting process. This allows remote denial of service against applications that expose the listener to untrusted peers. The impact is limited to availability; no confidentiality or integrity impact was identified.

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
54
EG Risk 54/100CISA 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
Severity87% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.
EPSS PROB
0.7%
EPSS %ILE
51st
KEV
Not listed

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

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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

September 21, 2026

Last Modified

September 22, 2026

Advisory Details (6)

Auto-updated Sep 21, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

GitHub - temporalio/tchannel-go at v1.22.1 · GitHub

https://github.com/temporalio/tchannel-go/tree/v1.22.1
github_commit

commit 0cb017f6870a (temporalio/tchannel-go)

Fix landed in temporalio/tchannel-go commit 0cb017f6870a — awaiting tagged release

https://github.com/temporalio/tchannel-go/commit/0cb017f6870a8420695abeb9a4560d39dadc4e2e
github_pr

Return errors on invalid call frames

Fix merged in temporalio/tchannel-go PR #14 on 2026-07-22 — awaiting tagged release

https://github.com/temporalio/tchannel-go/pull/14
github_commit

commit 1dcfa67262ec (temporalio/tchannel-go)

Fix landed in temporalio/tchannel-go commit 1dcfa67262ec — awaiting tagged release

https://github.com/temporalio/tchannel-go/commit/1dcfa67262ecd56a24f12940f4082549190cb5d1
generic

tchannel-go/fragmenting_reader.go at 8706a1ab5f617efd79dace7ab2d1d80cc1881df0 · temporalio/tchannel-go · GitHub

https://github.com/temporalio/tchannel-go/blob/8706a1ab5f617efd79dace7ab2d1d80cc1881df0/fragmenting_reader.go#L256-L308
github_commit

commit 8d8ca17342b3 (temporalio/tchannel-go)

Fix landed in temporalio/tchannel-go commit 8d8ca17342b3 — awaiting tagged release

https://github.com/temporalio/tchannel-go/commit/8d8ca17342b3620d3a6d5c1a825145595e7588ff

Vendor Advisories for CVE-2026-65653(1)

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 27× in last 7d / 53× 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. 2026-10-04 01:09 UTCEG score recompute
  2. 2026-10-04 01:09 UTCGHSA enrichment
  3. 2026-10-03 14:26 UTCEPSS rescore
  4. 2026-10-03 13:29 UTCGHSA enrichment
  5. 2026-10-03 01:48 UTCEG score recompute
  6. 2026-10-03 01:48 UTCGHSA enrichment
  7. 2026-10-02 17:56 UTCEPSS rescore
  8. 2026-10-02 14:08 UTCGHSA enrichment
  9. 2026-10-02 02:27 UTCEG score recompute
  10. 2026-10-02 02:27 UTCGHSA enrichment
  11. 2026-10-01 19:50 UTCEPSS rescore
  12. 2026-10-01 14:47 UTCGHSA enrichment
  13. 2026-10-01 03:06 UTCGHSA enrichment
  14. 2026-09-30 15:26 UTCEG score recompute
  15. 2026-09-30 15:26 UTCGHSA enrichment
  16. 2026-09-30 15:03 UTCEPSS rescore
  17. 2026-09-30 03:45 UTCGHSA enrichment
  18. 2026-09-29 16:05 UTCEG score recompute
  19. 2026-09-29 16:05 UTCGHSA enrichment
  20. 2026-09-29 04:24 UTCEG score recompute
  21. 2026-09-29 04:24 UTCGHSA enrichment
  22. 2026-09-28 16:43 UTCEG score recompute
  23. 2026-09-28 16:43 UTCGHSA enrichment
  24. 2026-09-28 13:51 UTCEPSS rescore
  25. 2026-09-28 04:53 UTCGHSA enrichment
Show 28 more
  1. 2026-09-27 17:12 UTCEG score recompute
  2. 2026-09-27 17:12 UTCGHSA enrichment
  3. 2026-09-27 05:32 UTCGHSA enrichment
  4. 2026-09-26 17:49 UTCEG score recompute
  5. 2026-09-26 17:48 UTCGHSA enrichment
  6. 2026-09-26 15:59 UTCEPSS rescore
  7. 2026-09-26 06:05 UTCEG score recompute
  8. 2026-09-26 06:05 UTCGHSA enrichment
  9. 2026-09-25 18:20 UTCGHSA enrichment
  10. 2026-09-25 06:18 UTCGHSA enrichment
  11. 2026-09-24 18:37 UTCEG score recompute
  12. 2026-09-24 18:37 UTCGHSA enrichment
  13. 2026-09-24 06:54 UTCGHSA enrichment
  14. 2026-09-23 19:13 UTCEG score recompute
  15. 2026-09-23 19:13 UTCGHSA enrichment
  16. 2026-09-23 17:54 UTCEPSS rescore
  17. 2026-09-23 07:33 UTCGHSA enrichment
  18. 2026-09-22 19:52 UTCEG score recompute
  19. 2026-09-22 19:52 UTCGHSA enrichment
  20. 2026-09-22 15:46 UTCGHSA enrichment
  21. 2026-09-22 04:06 UTCGHSA enrichment
  22. 2026-09-21 16:25 UTCEG score recompute
  23. 2026-09-21 16:25 UTCGHSA enrichment
  24. 2026-09-21 15:35 UTCEG score recompute
  25. 2026-09-21 15:35 UTCGHSA enrichment
  26. 2026-09-21 12:30 UTCEG score recompute
  27. 2026-09-21 11:45 UTCEG score recompute
  28. 2026-09-21 11:45 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-65653?
CVE-2026-65653 is a high vulnerability published on September 21, 2026. github.com/temporalio/tchannel-go did not reject TChannel call fragments containing checksum metadata but no length-prefixed argument chunks. The fragment reader left its chunk slice empty and then unconditionally selected the first element. A network peer can supply such a malformed call fragment,…
When was CVE-2026-65653 disclosed?
CVE-2026-65653 was first published on September 21, 2026, with the most recent update on September 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-65653 actively exploited?
CVE-2026-65653 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-65653?
CVE-2026-65653 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-65653?
An upstream fix for CVE-2026-65653 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-65653 are linked in the Vendor Advisories panel on this page.

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