CVE-2026-53776

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (49th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
9.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Perry before 0.5.1166 contains a JWT validation vulnerability that allows remote attackers to bypass token expiration by exploiting the unconditional setting of validate_exp = false in the verify_decode helper within the stdlib JWT verification path. Attackers in possession of a previously issued bearer token can present expired tokens to any jwt.verify() call and retain authenticated access indefinitely, bypassing force-expired sessions such as user logout or administrative revocation.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100

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 (value × EchelonGraph’s weight)
Severity91% × 45%
The EG Score, 9.1 of 10.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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: 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
0.6%
EPSS %ILE
49th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; 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 (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

June 16, 2026

Last Modified

July 14, 2026

Advisory Details (3)

Auto-updated Sep 16, 2026
Patch available. Sources: github_release, github.
Web page

Perry < 0.5.1166 JWT Expiration Bypass via verify_decode | Advisories | VulnCheck

https://www.vulncheck.com/advisories/perry-jwt-expiration-bypass-via-verify-decode
GitHub advisoryMentions a patch (unverified)

stdlib Fails to Enforce JWT Token Expiration in verify_decode · Advisory · PerryTS/perry · GitHub

https://github.com/PerryTS/perry/security/advisories/GHSA-5324-c68v-8w62
GitHub release Patch Available

v0.5.1166

Patch available: PerryTS/perry v0.5.1166

https://github.com/PerryTS/perry/releases/v0.5.1166

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 33× 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 it from the CNA feed. 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). Most recent first.

Showing the most recent 100 of 165 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 65 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 06:19 UTCEG score recompute
  2. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
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  11. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 49th percentile
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  19. 2026-10-03 17:21 UTCOSV refresh
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  1. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  4. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  9. 2026-09-14 03:31 UTCEG score recompute
  10. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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  12. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
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  20. 2026-08-30 22:48 UTCEG score recompute
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  27. 2026-08-24 23:24 UTCEG score recompute
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  29. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  30. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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  51. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.4% · 28th percentile
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  74. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  75. 2026-07-29 03:03 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-53776?
CVE-2026-53776 is a critical-severity vulnerability; its CVE record was published on June 16, 2026. Perry before 0.5.1166 contains a JWT validation vulnerability that allows remote attackers to bypass token expiration by exploiting the unconditional setting of validateexp = false in the verifydecode helper within the stdlib JWT verification path. Attackers in possession of a previously issued…
When was CVE-2026-53776 made public?
CVE-2026-53776 was made public on June 14, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on June 16, 2026. EchelonGraph's copy of the record carries a last-modified date of July 14, 2026; the record at its source may have been updated since.
Is CVE-2026-53776 actively exploited?
CVE-2026-53776 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53776?
CVE-2026-53776 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53776?
A fix for CVE-2026-53776 is available: update to the fixed version the vendor names in its advisory.

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