cpp-httplib is a C++ header-only HTTP/HTTPS library. In versions 0.33.0 through 0.50.0, the TLS-enabled WebSocket client frees the TLS session before closing the WebSocket that still uses it, producing a use-after-free. In WebSocketClient::shutdown_and_close the SSL object is freed and the pointer cleared, but the subsequent WebSocket close still sends a close frame through the SSL socket stream, which holds a raw copy of the now-dangling session pointer and reads from and writes to the freed memory. The same freed-then-used ordering is reachable through the client's destructor and its connect path, so ordinary teardown of a secure WebSocket connection triggers the defect. This issue is fixed in version 0.50.1.
CVE-2026-77358
HIGHPre-NVD 8.28.2—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 79% 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
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.2
- EG Score
- 8.2(medium)
- EG Risk
- 42(Track)EG Risk 42/100SSVC: 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 computedSeverity82% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 21%
- KEV
- Not listed
Published
August 27, 2026
Last Modified
August 28, 2026
Advisory Details (2)
Auto-updated Aug 27, 2026🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github_commit Patch Available
commit 2f986fd5e56e (yhirose/cpp-httplib)
Patch available: yhirose/cpp-httplib v0.50.1 (contains commit 2f986fd5e56e)
https://github.com/yhirose/cpp-httplib/commit/2f986fd5e56e7c5f686d965174516360930f371dgithub Patch Available🟡 PoC Available
Use-after-free of TLS session in WebSocketClient::shutdown_and_close() · Advisory · yhirose/cpp-httplib · GitHub
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-w7p7-f35j-mw7qWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× 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.
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-29 00:09 UTCEG score recompute
- 2026-08-28 21:42 UTCEPSS rescore
- 2026-08-28 00:30 UTCEG score recompute
- 2026-08-27 23:23 UTCEG score recompute
- 2026-08-27 23:23 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-77358?
CVE-2026-77358 is a high vulnerability published on August 27, 2026. cpp-httplib is a C++ header-only HTTP/HTTPS library. In versions 0.33.0 through 0.50.0, the TLS-enabled WebSocket client frees the TLS session before closing the WebSocket that still uses it, producing a use-after-free. In WebSocketClient::shutdownandclose the SSL object is freed and the pointer…
When was CVE-2026-77358 disclosed?
CVE-2026-77358 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77358 actively exploited?
CVE-2026-77358 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 79.2% of all scored CVEs.
What is the CVSS score of CVE-2026-77358?
CVE-2026-77358 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-77358?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77358, 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
Explore the affected products and dependency analysis for CVE-2026-77358
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