No exploitation reportedFix available

CVE-2023-49295

Q: Is CVE-2023-49295 actively exploited?

Active exploitation of CVE-2023-49295 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2023-49295?

CVE-2023-49295 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2024-01-10
Fixed in0.40.1 · 0.39.4 · 0.38.2 · 0.37.7
WeaknessCWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

quic-go is an implementation of the QUIC protocol (RFC 9000, RFC 9001, RFC 9002) in Go. An attacker can cause its peer to run out of memory sending a large number of PATH_CHALLENGE frames. The receiver is supposed to respond to each PATH_CHALLENGE frame with a PATH_RESPONSE frame. The attacker can prevent the receiver from sending out (the vast majority of) these PATH_RESPONSE frames by collapsing the peers congestion window (by selectively acknowledging received packets) and by manipulating the peer's RTT estimate. This vulnerability has been patched in versions 0.37.7, 0.38.2 and 0.39.4.

Timeline

dates in UTC

2024-01-1022:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-49295?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-49295?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD

Quic-go project quic-go

Branch	Affected	Fixed in	Source
0.40	≥ 0.40.0, < 0.40.1	0.40.1	OSV
0.39	≥ 0.39.0, < 0.39.4	0.39.4	NVD · OSV
0.38	≥ 0.38.0, < 0.38.2	0.38.2	NVD · OSV
0.37	< 0.37.7	0.37.7	NVD · OSV
0.40	= 0.40.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Quic-go project quic-go to 0.40.1 · 0.39.4 · 0.38.2 · 0.37.7

Advisories and patches

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-01-11
OpenCVESSVC decisionnone—
CNACVSS 3.16.4read 2026-10-23
NVDCVSS 3.16.5read 2026-10-23
CNAweakness (CWE)CWE-400read 2026-10-23
FIRST EPSSEPSS score1.2 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Published: 2024-01-10
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-49295?

Is CVE-2023-49295 actively exploited?

Active exploitation of CVE-2023-49295 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-49295?

CVE-2023-49295 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

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