CVE-2026-77358

HIGHPre-NVD 8.28.2
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (36th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
8.2EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.2Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
68
EG Risk 68/100

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 (value × EchelonGraph’s weight)
Severity82% × 45%
The EG Score, 8.2 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
36th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 27, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Aug 27, 2026
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/2f986fd5e56e7c5f686d965174516360930f371d
GitHub advisoryMentions a patch (unverified)

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-mw7q

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
cpp-httplib0.11.4+ds-1 ... 0.41.0+ds-3~bpo13+1 (27 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
cpp-httplib0.18.7-1 ... 0.41.0+ds-3~bpo13+1 (9 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
cpp-httplib0.18.7-1 ... 0.41.0+ds-3~bpo13+1 (8 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 58× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 93 are merged into the row they repeat.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-10-13 06:58 UTCEG score recompute
  3. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-10-12 15:37 UTCEG score recompute
  5. 2026-10-11 19:23 UTCEG score recompute
  6. 2026-10-11 16:39 UTCEG score recompute
  7. 2026-10-11 13:58 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  10. 2026-10-10 01:44 UTCEG score recompute
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  12. 2026-10-09 02:53 UTCEG score recompute
  13. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  14. 2026-10-08 01:11 UTCEG score recompute
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  16. 2026-10-06 19:17 UTCEG score recompute
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  18. 2026-10-05 19:27 UTCEG score recompute
  19. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  20. 2026-10-05 07:26 UTCEG score recompute
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  22. 2026-10-03 19:21 UTCEG score recompute
  23. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  24. 2026-10-02 19:28 UTCEG score recompute
  25. 2026-10-01 19:52 UTCEG score recompute
Show 66 more
  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-09-30 19:53 UTCEG score recompute
  3. 2026-09-29 15:30 UTCEG score recompute
  4. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  5. 2026-09-29 03:43 UTCEG score recompute
  6. 2026-09-28 15:47 UTCEG score recompute
  7. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  8. 2026-09-27 15:55 UTCEG score recompute
  9. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  10. 2026-09-27 04:08 UTCEG score recompute
  11. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  12. 2026-09-26 15:49 UTCEG score recompute
  13. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  14. 2026-09-24 20:12 UTCEG score recompute
  15. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-09-23 20:37 UTCEG score recompute
  17. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  18. 2026-09-22 21:02 UTCEG score recompute
  19. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  20. 2026-09-22 09:15 UTCEG score recompute
  21. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  22. 2026-09-20 21:24 UTCEG score recompute
  23. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  24. 2026-09-19 21:49 UTCEG score recompute
  25. 2026-09-18 21:29 UTCEG score recompute
  26. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  27. 2026-09-17 20:53 UTCEG score recompute
  28. 2026-09-16 19:02 UTCEG score recompute
  29. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  30. 2026-09-16 06:34 UTCEG score recompute
  31. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  32. 2026-09-15 06:58 UTCEG score recompute
  33. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  34. 2026-09-13 19:35 UTCEG score recompute
  35. 2026-09-12 20:00 UTCEG score recompute
  36. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  37. 2026-09-11 20:25 UTCEG score recompute
  38. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  39. 2026-09-10 20:51 UTCEG score recompute
  40. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  41. 2026-09-09 00:37 UTCEG score recompute
  42. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  43. 2026-09-07 18:38 UTCEG score recompute
  44. 2026-09-06 19:02 UTCEG score recompute
  45. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  46. 2026-09-05 19:26 UTCEG score recompute
  47. 2026-09-04 19:51 UTCEG score recompute
  48. 2026-09-04 07:54 UTCEG score recompute
  49. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  50. 2026-09-02 20:27 UTCEG score recompute
  51. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  52. 2026-09-01 19:10 UTCEG score recompute
  53. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  54. 2026-09-01 07:19 UTCEG score recompute
  55. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  56. 2026-08-31 19:32 UTCEG score recompute
  57. 2026-08-31 18:34 UTCEG score recompute
  58. 2026-08-30 23:29 UTCEG score recompute
  59. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  60. 2026-08-30 11:42 UTCEG score recompute
  61. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  62. 2026-08-29 00:09 UTCEG score recompute
  63. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  64. 2026-08-28 00:30 UTCEG score recompute
  65. 2026-08-27 23:23 UTCEG score recomputeFirst assessed: 8.2 HIGH
  66. 2026-08-27 23:23 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-77358?
CVE-2026-77358 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-77358 published?
The CVE record for CVE-2026-77358 was published on August 27, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-77358 actively exploited?
CVE-2026-77358 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77358?
CVE-2026-77358 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77358?
A fix for CVE-2026-77358 is available: update to the fixed version the vendor names in its advisory.

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