CVE-2023-39533

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 1.3%, top 31% 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, nvd
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 7.5Exploit: Elevated riskExposed: 0

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

go-libp2p is the Go implementation of the libp2p Networking Stack. Prior to versions 0.27.8, 0.28.2, and 0.29.1 malicious peer can use large RSA keys to run a resource exhaustion attack & force a node to spend time doing signature verification of the large key. This vulnerability is present in the core/crypto module of go-libp2p and can occur during the Noise handshake and the libp2p x509 extension verification step. To prevent this attack, go-libp2p versions 0.27.8, 0.28.2, and 0.29.1 restrict RSA keys to <= 8192 bits. To protect one's application, it is necessary to update to these patch releases and to use the updated Go compiler in 1.20.7 or 1.19.12. There are no known workarounds for this issue.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
2%
EPSS %ILE
73%
KEV
Not listed

Published

August 8, 2023

Last Modified

September 1, 2026

Advisory Details (9)

Auto-updated Sep 1, 2026
Patch available. Sources: github, github_pr, github_commit.
generic

NRDAX-T0205 - Pre-Handshake Crypto CPU Burn · NRDAX

https://nrdax.com/techniques/NRDAX-T0205-pre-handshake-crypto-cpu-burn
github_commit

commit e30fcf7dfd47 (libp2p/go-libp2p)

Fix landed in libp2p/go-libp2p commit e30fcf7dfd47 — awaiting tagged release

https://github.com/libp2p/go-libp2p/commit/e30fcf7dfd4715ed89a5e68d7a4f774d3b9aa92d
github_commit

commit 445be526aea4 (libp2p/go-libp2p)

Fix landed in libp2p/go-libp2p commit 445be526aea4 — awaiting tagged release

https://github.com/libp2p/go-libp2p/commit/445be526aea4ee0b1fa5388aa65d32b2816d3a00
github_commit

commit 0cce607219f3 (libp2p/go-libp2p)

Fix landed in libp2p/go-libp2p commit 0cce607219f3 — awaiting tagged release

https://github.com/libp2p/go-libp2p/commit/0cce607219f3710addc7e18672cffd1f1d912fbb
github_commit

commit 2350afd2e8ab (golang/go)

Fix landed in golang/go commit 2350afd2e8ab — awaiting tagged release

https://github.com/golang/go/commit/2350afd2e8ab054390e284c95d5b089c142db017
github_pr Patch Available

update qtls to restrict RSA keys in certificates to <= 8192 bits

Patch available: quic-go/quic-go v0.42.0 (PR #4012 merged 2023-08-03)

https://github.com/quic-go/quic-go/pull/4012
github_pr Patch Available

core/crypto: restrict RSA keys to <= 8192 bits

Patch available: libp2p/go-libp2p v0.35.3 (PR #2454 merged 2023-08-03)

https://github.com/libp2p/go-libp2p/pull/2454
generic

crypto/tls: verifying certificate chains containing large RSA keys is slow [CVE-2023-29409] · Issue #61460 · golang/go · GitHub

https://github.com/golang/go/issues/61460
github Patch Available

libp2p nodes vulnerable to attack using large RSA keys · Advisory · libp2p/go-libp2p · GitHub

https://github.com/libp2p/go-libp2p/security/advisories/GHSA-876p-8259-xjgg

Vendor Advisories for CVE-2023-39533(1)

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

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/libp2p/go-libp2p0.29.00.29.1—

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 6× in last 7d / 30× 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.

Showing the most recent 100 of 178 total refreshes for this CVE.

  1. 2026-09-18 19:25 UTCEPSS rescore
  2. 2026-09-17 19:25 UTCEPSS rescore
  3. 2026-09-16 14:06 UTCEPSS rescore
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  17. 2026-09-02 14:09 UTCEPSS rescore
  18. 2026-09-01 22:20 UTCVendor advisory
  19. 2026-09-01 21:43 UTCEG score recompute
  20. 2026-09-01 21:43 UTCVendor advisory
  21. 2026-09-01 13:51 UTCEPSS rescore
  22. 2026-08-30 19:15 UTCEPSS rescore
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  24. 2026-08-28 21:39 UTCEPSS rescore
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  1. 2026-08-26 14:44 UTCEPSS rescore
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  9. 2026-08-18 13:46 UTCEPSS rescore
  10. 2026-08-17 13:45 UTCEPSS rescore
  11. 2026-08-17 10:55 UTCOSV refresh
  12. 2026-08-16 14:54 UTCEPSS rescore
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  26. 2026-08-03 10:34 UTCEPSS rescore
  27. 2026-08-03 10:34 UTCEPSS rescore
  28. 2026-08-02 05:28 UTCOSV refresh
  29. 2026-08-02 02:25 UTCEPSS rescore
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  44. 2026-07-23 14:16 UTCEPSS rescore
  45. 2026-07-23 02:25 UTCEG score recompute
  46. 2026-07-22 23:12 UTCEG score recompute
  47. 2026-07-22 14:06 UTCEPSS rescore
  48. 2026-07-21 15:23 UTCEPSS rescore
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  50. 2026-07-20 17:06 UTCEPSS rescore
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  59. 2026-07-15 13:19 UTCOSV refresh
  60. 2026-07-15 01:58 UTCEPSS rescore
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  67. 2026-07-11 08:26 UTCEPSS rescore
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  69. 2026-07-09 19:08 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-39533?
CVE-2023-39533 is a high vulnerability published on August 8, 2023. go-libp2p is the Go implementation of the libp2p Networking Stack. Prior to versions 0.27.8, 0.28.2, and 0.29.1 malicious peer can use large RSA keys to run a resource exhaustion attack & force a node to spend time doing signature verification of the large key. This vulnerability is present in the…
When was CVE-2023-39533 disclosed?
CVE-2023-39533 was first published in the National Vulnerability Database on August 8, 2023, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-39533 actively exploited?
CVE-2023-39533 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 26.9% of all scored CVEs.
What is the CVSS score of CVE-2023-39533?
CVE-2023-39533 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2023-39533?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-39533, 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.

Dependency Blast Radius

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