CVE-2026-88390

HIGHPre-NVD 7.77.7—
EchelonGraph scoreHIGH confidence

Score 7.7 from GitHub Security Advisory (severity: HIGH) published 2026-09-24. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this weekElevated
7.7EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.7Exploit: Elevated riskExposed services: Not assessed

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

An out-of-bounds write vulnerability in jslGetTokenValueAsString() in Espruino 2v29 (commit bffc6d0) allows crafted JavaScript input containing an overlong token to trigger a one-byte write beyond the JsLex.token buffer in RELEASE/NO_ASSERT builds. The out-of-bounds write corrupts the adjacent tokenValue pointer, resulting in memory corruption and potentially causing application crashes or denial of service.

CVSS v3
7.7
EG Score
7.7HIGHhigh confidence
EG Risk
51
EG Risk 51/100CISA 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
Severity77% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
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
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

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 public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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 24, 2026

Last Modified

September 24, 2026

Advisory Details (2)

Auto-updated Sep 24, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit

commit ecd7d43e084b (espruino/Espruino)

Fix landed in espruino/Espruino commit ecd7d43e084b — awaiting tagged release

https://github.com/espruino/Espruino/commit/ecd7d43e084ba9aafa8245609347fe0f4383b38c
generic

[Bug]jslGetTokenValueAsString writes token[64] for a ≥64-byte token: 1-byte out-of-bounds write masked by assert; real struct OOB write under RELEASE/NO_ASSERT (CWE-787) · Issue #2744 · espruino/Espruino · GitHub

https://github.com/espruino/Espruino/issues/2744

Vendor Advisories for CVE-2026-88390(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 24× in last 7d / 42× 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 03:30 UTCGHSA enrichment
  2. 2026-10-03 15:13 UTCEG score recompute
  3. 2026-10-03 15:13 UTCGHSA enrichment
  4. 2026-10-03 02:55 UTCEG score recompute
  5. 2026-10-03 02:55 UTCGHSA enrichment
  6. 2026-10-02 14:35 UTCGHSA enrichment
  7. 2026-10-02 02:04 UTCEG score recompute
  8. 2026-10-02 02:04 UTCGHSA enrichment
  9. 2026-10-01 19:51 UTCEPSS rescore
  10. 2026-10-01 13:43 UTCGHSA enrichment
  11. 2026-10-01 01:25 UTCEG score recompute
  12. 2026-10-01 01:25 UTCGHSA enrichment
  13. 2026-09-30 15:04 UTCEPSS rescore
  14. 2026-09-30 13:08 UTCGHSA enrichment
  15. 2026-09-30 00:49 UTCEG score recompute
  16. 2026-09-30 00:49 UTCGHSA enrichment
  17. 2026-09-29 12:31 UTCGHSA enrichment
  18. 2026-09-29 00:13 UTCEG score recompute
  19. 2026-09-29 00:13 UTCGHSA enrichment
  20. 2026-09-28 13:52 UTCEPSS rescore
  21. 2026-09-28 11:55 UTCGHSA enrichment
  22. 2026-09-27 23:37 UTCEG score recompute
  23. 2026-09-27 23:37 UTCGHSA enrichment
  24. 2026-09-27 13:48 UTCEPSS rescore
  25. 2026-09-27 11:18 UTCGHSA enrichment
Show 17 more
  1. 2026-09-26 22:56 UTCEG score recompute
  2. 2026-09-26 22:56 UTCGHSA enrichment
  3. 2026-09-26 15:59 UTCEPSS rescore
  4. 2026-09-26 10:37 UTCEG score recompute
  5. 2026-09-26 10:36 UTCGHSA enrichment
  6. 2026-09-25 22:13 UTCGHSA enrichment
  7. 2026-09-25 09:34 UTCEG score recompute
  8. 2026-09-25 09:34 UTCGHSA enrichment
  9. 2026-09-24 21:16 UTCEG score recompute
  10. 2026-09-24 21:16 UTCGHSA enrichment
  11. 2026-09-24 19:36 UTCGHSA enrichment
  12. 2026-09-24 19:07 UTCEG score recompute▲ 7.70
  13. 2026-09-24 19:07 UTCGHSA enrichment
  14. 2026-09-24 19:06 UTCMITRE cvelistV5CVSS v3 → 7.7 · severity → HIGH
  15. 2026-09-24 17:33 UTCNVD update
  16. 2026-09-24 16:47 UTCEG score recompute
  17. 2026-09-24 16:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-88390?
CVE-2026-88390 is a high vulnerability published on September 24, 2026. An out-of-bounds write vulnerability in jslGetTokenValueAsString() in Espruino 2v29 (commit bffc6d0) allows crafted JavaScript input containing an overlong token to trigger a one-byte write beyond the JsLex.token buffer in RELEASE/NO_ASSERT builds. The out-of-bounds write corrupts the adjacent…
When was CVE-2026-88390 disclosed?
CVE-2026-88390 was first published on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-88390 actively exploited?
CVE-2026-88390 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-88390?
CVE-2026-88390 has a CVSS v3.1 base score of 7.7 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-88390?
An upstream fix for CVE-2026-88390 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-2026-88390 are linked in the Vendor Advisories panel on this page.

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