webtransport-go is an implementation of the WebTransport protocol. Prior to 0.11.1, Session.parseNextCapsule() in session.go skips an unknown WebTransport capsule on the HTTP/3 request stream by calling io.ReadAll on the capsule reader, retaining the complete declared capsule body in memory. A malicious peer can send a large unknown capsule and cause a client or server to allocate memory for the full payload; QUIC flow control does not bound the total retained allocation because reading advances the flow-control window while the received bytes remain in memory. The resulting memory and resource exhaustion can disrupt or crash the affected process. This issue is fixed in version 0.11.1.
CVE-2026-57497
MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 60% 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(medium)
- EG Risk
- 39(Track)EG Risk 39/100SSVC: 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 computedSeverity53% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 40%
- KEV
- Not listed
Published
July 24, 2026
Last Modified
September 14, 2026
Advisory Details (4)
Auto-updated Sep 14, 2026Patch available. Sources: github_commit, github_release, github, github_pr.
github_release Patch Available
v0.11.1
Patch available: quic-go/webtransport-go v0.11.1
https://github.com/quic-go/webtransport-go/releases/tag/v0.11.1github_commit Patch Available
commit 3aecd1173657 (quic-go/webtransport-go)
Patch available: quic-go/webtransport-go v0.11.1 (contains commit 3aecd1173657)
https://github.com/quic-go/webtransport-go/commit/3aecd11736579530ff067651c30a543eb0b4b8c4github_pr Patch Available
avoid buffering skipped capsules
Patch available: quic-go/webtransport-go v0.12.0 (PR #290 merged 2026-06-20)
https://github.com/quic-go/webtransport-go/pull/290github Patch Available
Memory Exhaustion Attack due to Buffering of Unknown Capsules · Advisory · quic-go/webtransport-go · GitHub
https://github.com/quic-go/webtransport-go/security/advisories/GHSA-g35j-m5xg-vh3qVendor Advisories for CVE-2026-57497(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)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| github.com/quic-go/webtransport-go | — | 0.11.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× 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.
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-18 10:48 UTCEG score recompute
- 2026-09-17 19:31 UTCEPSS rescore
- 2026-09-17 09:13 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescore
- 2026-09-16 06:39 UTCEG score recompute
- 2026-09-16 05:15 UTCEPSS rescore
- 2026-09-14 20:27 UTCEG score recompute
- 2026-09-14 20:16 UTCEG score recompute
- 2026-09-14 18:08 UTCEG score recompute
- 2026-07-30 16:03 UTCEG score recompute
- 2026-07-27 11:17 UTCEG score recompute
- 2026-07-24 21:12 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-57497?
CVE-2026-57497 is a medium vulnerability published on July 24, 2026. webtransport-go is an implementation of the WebTransport protocol. Prior to 0.11.1, Session.parseNextCapsule() in session.go skips an unknown WebTransport capsule on the HTTP/3 request stream by calling io.ReadAll on the capsule reader, retaining the complete declared capsule body in memory. A…
When was CVE-2026-57497 disclosed?
CVE-2026-57497 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-57497 actively exploited?
CVE-2026-57497 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 60.2% of all scored CVEs.
What is the CVSS score of CVE-2026-57497?
CVE-2026-57497 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-57497?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-57497, 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
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-57497
Is Your Infrastructure Affected by CVE-2026-57497?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.