CVE-2026-88355

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-24. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Elevated

Also known asEUVD-2026-86286 (ENISA EUVD) · GHSA-8v6x-g49v-x5cf (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan mitigationThe upstream fix is not in a release yet: until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

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

An incorrect buffer size calculation vulnerability exists in tinyexpr commit 4a7456e in new_expr(). For arity-0 expression nodes, including constants, variables, and zero-argument functions, the function allocates less memory than sizeof(te_expr) but treats the returned allocation as a complete te_expr object. This results in undefined behavior and can cause deterministic process termination in UBSan-instrumented builds.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: An upstream fix is merged but not yet in a tagged release. Until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it.
EPSS PROB
0.4%
EPSS %ILE
36th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

An upstream fix is merged but not yet in a tagged release. Until the release ships, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high, then apply it.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 24, 2026

Last Modified

October 6, 2026

Advisory Details (2)

Auto-updated Oct 6, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
GitHub commit

commit fe7459728c2a (szaydel/tinyexpr)

Fix landed in szaydel/tinyexpr commit fe7459728c2a — awaiting tagged release

https://github.com/szaydel/tinyexpr/commit/fe7459728c2ab8d2f91365abe56601cdd0e24f9b
Web page

[Bug]undersized heap allocation for arity-0 expression nodes in new_expr() — UBSAN object-size violation on any valid expression (CWE-131) · Issue #145 · codeplea/tinyexpr · GitHub

https://github.com/codeplea/tinyexpr/issues/145

Vendor Advisories for CVE-2026-88355(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 8× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-12 16:35 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-11-11 16:41 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  3. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  5. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  6. 2026-11-08 10:27 UTCEchelonGraph re-scored
  7. 2026-11-08 10:27 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  10. 2026-11-05 16:39 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  14. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-11-01 02:25 UTCEchelonGraph re-scored
  16. 2026-11-01 02:25 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  19. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  20. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  22. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  23. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-10-25 13:53 UTCEchelonGraph re-scored
  25. 2026-10-24 18:32 UTCEchelonGraph re-scored
Show 65 more
  1. 2026-10-24 18:32 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  3. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  4. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  5. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  6. 2026-10-20 17:52 UTCEchelonGraph re-scored
  7. 2026-10-20 17:51 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  9. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  10. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  11. 2026-10-18 03:03 UTCEchelonGraph re-scored
  12. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  13. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  14. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  15. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  16. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  17. 2026-10-13 05:03 UTCEchelonGraph re-scored
  18. 2026-10-13 05:03 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  19. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  20. 2026-10-12 14:49 UTCEchelonGraph re-scored
  21. 2026-10-12 04:36 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  22. 2026-10-11 19:15 UTCEchelonGraph re-scored
  23. 2026-10-11 16:32 UTCEchelonGraph re-scored
  24. 2026-10-11 15:35 UTCEchelonGraph re-scored
  25. 2026-10-11 15:35 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  26. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  27. 2026-10-11 13:48 UTCEchelonGraph re-scored
  28. 2026-10-11 02:52 UTCEchelonGraph re-scored
  29. 2026-10-11 02:51 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  30. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  31. 2026-10-10 14:07 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  32. 2026-10-10 01:22 UTCEchelonGraph re-scored
  33. 2026-10-10 01:22 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  34. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  35. 2026-10-09 12:38 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  36. 2026-10-08 21:41 UTCEchelonGraph re-scored
  37. 2026-10-08 21:41 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  38. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  39. 2026-10-08 08:45 UTCEchelonGraph re-scored
  40. 2026-10-08 08:45 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  41. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  42. 2026-10-07 20:01 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  43. 2026-10-07 07:17 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  44. 2026-10-06 18:33 UTCEchelonGraph re-scored
  45. 2026-10-06 18:33 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-10-06 17:47 UTCEchelonGraph re-scoredFirst assessed: 7.5 HIGH
  47. 2026-10-06 17:47 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf
  48. 2026-10-06 17:46 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
  49. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  50. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  51. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  52. 2026-10-04 01:33 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf
  53. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  54. 2026-10-01 00:16 UTCEchelonGraph re-scored
  55. 2026-10-01 00:16 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf
  56. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  57. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
  58. 2026-09-27 22:29 UTCEchelonGraph re-scored
  59. 2026-09-27 22:29 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf
  60. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
  61. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 3rd percentile
  62. 2026-09-24 21:16 UTCGHSA enrichmentGHSA-8v6x-g49v-x5cf
  63. 2026-09-24 16:30 UTCNVD update
  64. 2026-09-24 15:32 UTCEchelonGraph re-scored
  65. 2026-09-24 15:31 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-88355?
CVE-2026-88355 is a high-severity vulnerability; its CVE record was published on September 24, 2026. An incorrect buffer size calculation vulnerability exists in tinyexpr commit 4a7456e in new_expr(). For arity-0 expression nodes, including constants, variables, and zero-argument functions, the function allocates less memory than sizeof(te_expr) but treats the returned allocation as a complete…
When was the CVE record for CVE-2026-88355 published?
The CVE record for CVE-2026-88355 was published on September 24, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 6, 2026; the record at its source may have been updated since.
Is CVE-2026-88355 actively exploited?
CVE-2026-88355 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-88355?
CVE-2026-88355 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-88355?
An upstream fix for CVE-2026-88355 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-2026-88355 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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