CVE-2026-45271

MEDIUMPre-NVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. 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
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. Picotls implements its own ASN.1 validation helper, which is used by the minicrypto backend while parsing local PKCS#8 private keys. Prior to commit c14231d801407640bc42c2dcf92783409ea6a7c7, the validator recursively descends into constructed ASN.1 elements without enforcing a maximum nesting depth. If an application loads an attacker-supplied private-key file through ptls_minicrypto_load_private_key(), or otherwise calls the public ASN.1 validation API on untrusted DER, a crafted deeply nested ASN.1 structure can exhaust the process stack and crash the application. Note that the libcrypto (OpenSSL) backend does not use the ASN.1 validation helper of picotls, and therefore is immune to this vulnerability. The vulnerability has been addressed in commit c14231d801407640bc42c2dcf92783409ea6a7c7.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: Track

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
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 21, 2026

Last Modified

August 25, 2026

Advisory Details (2)

Auto-updated Aug 21, 2026
Patch available. Sources: github_commit, github.
github Patch Available

infinite recursion in the minicrypto ASN.1 decoder · Advisory · h2o/picotls · GitHub

https://github.com/h2o/picotls/security/advisories/GHSA-84f5-m5x2-82q4
github_commit

commit c14231d80140 (h2o/picotls)

Fix landed in h2o/picotls commit c14231d80140 — awaiting tagged release

https://github.com/h2o/picotls/commit/c14231d801407640bc42c2dcf92783409ea6a7c7

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 12× 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. 2026-08-27 14:25 UTCEPSS rescore
  2. 2026-08-26 17:51 UTCEG score recompute
  3. 2026-08-26 14:46 UTCEPSS rescore
  4. 2026-08-25 15:23 UTCEG score recompute
  5. 2026-08-25 14:35 UTCEG score recompute
  6. 2026-08-25 13:49 UTCEPSS rescore
  7. 2026-08-25 03:54 UTCEG score recompute
  8. 2026-08-24 01:44 UTCEG score recompute
  9. 2026-08-23 00:19 UTCEPSS rescore
  10. 2026-08-21 21:24 UTCEG score recompute
  11. 2026-08-21 21:05 UTCEG score recompute
  12. 2026-08-21 21:04 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-45271?
CVE-2026-45271 is a medium vulnerability published on August 21, 2026. Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. Picotls implements its own ASN.1 validation helper, which is used by the minicrypto backend while parsing local PKCS#8 private keys. Prior to commit…
When was CVE-2026-45271 disclosed?
CVE-2026-45271 was first published in the National Vulnerability Database on August 21, 2026, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45271 actively exploited?
CVE-2026-45271 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.4% of all scored CVEs.
What is the CVSS score of CVE-2026-45271?
CVE-2026-45271 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-45271?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45271, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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