CVE-2023-39533 | libp2p nodes vulnerable to attack using large RSA keys

Exp

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.

Published: 2023-08-08 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2023-39533

EPSS CVSS CWE GHSA Exploit-DB Affected OS Tracker

Conclusion & alert: CVE-2023-39533 is rated High Exploit Risk (67.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.08%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-39533

EDB-ID	Source	Kind	Published	Link
—	nvd_ref	exploit_tag		Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-39533

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.11%	1.08%	+0.97%
2	2025-11-21	1.17%	0.11%	-1.05%
3	2025-11-18	—	1.17%	—

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-39533

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]

Weakness enumeration for CVE-2023-39533

CWE-770 MITRE ↗

GitHub Security Advisory for CVE-2023-39533

GHSA-876p-8259-xjgg · Severity: high · Ecosystem: go — libp2p nodes vulnerable to attack using large RSA keys

OS Trackers for CVE-2023-39533

vendor	priority	summary	link
`alpine`	high	CVE-2023-39533: 1 source package rows (go); 75 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 75.	https://security.alpinelinux.org/vuln/CVE-2023-39533
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2023-39533

Affected software / configurations for CVE-2023-39533

Vendor	Product	Version	Raw CPE
libp2p	go-libp2p	< 0.27.8	cpe:2.3:a:libp2p:go-libp2p::::::go::*
libp2p	go-libp2p	>= 0.28.0, < 0.28.2	cpe:2.3:a:libp2p:go-libp2p::::::go::*
libp2p	go-libp2p	0.29.0	cpe:2.3:a:libp2p:go-libp2p:0.29.0:::::go::

References for CVE-2023-39533

URL	Tags
https://github.com/golang/go/commit/2350afd2e8ab054390e284c95d5b089c142db017	Not Applicable Patch
https://github.com/golang/go/issues/61460	Issue Tracking Not Applicable Vendor Advisory
https://github.com/libp2p/go-libp2p/commit/0cce607219f3710addc7e18672cffd1f1d912fbb	Patch
https://github.com/libp2p/go-libp2p/commit/445be526aea4ee0b1fa5388aa65d32b2816d3a00	Patch
https://github.com/libp2p/go-libp2p/commit/e30fcf7dfd4715ed89a5e68d7a4f774d3b9aa92d	Patch
https://github.com/libp2p/go-libp2p/pull/2454	Exploit Patch Vendor Advisory
https://github.com/libp2p/go-libp2p/security/advisories/GHSA-876p-8259-xjgg	Patch Vendor Advisory
https://github.com/quic-go/quic-go/pull/4012	Patch Third Party Advisory

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