CVE-2026-82208Network attack vector

Certificate validation bypass via cached store reinstall

Published Sep 6, 2026 · Updated Sep 8, 2026

Improper certificate validation in curl allows man-in-the-middle attackers to make libcurl accept a certificate rejected by a selected trust store. In lib/vtls/wolfssl.c, the cached-store path fails to set the one-time X.509-store setup flag, so libcurl repopulates the cached store after the callback returns. Exposure requires a wolfSSL-backed application that enables CA caching, replaces the store in CURLOPT_SSL_CTX_FUNCTION, and connects through an attacker-controlled TLS endpoint.

CVSS severity4.8
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in curl allows man-in-the-middle attackers to make libcurl accept a certificate rejected by a selected trust store. In lib/vtls/wolfssl.c, the cached-store path fails to set the one-time X.509-store setup flag, so libcurl repopulates the cached store after the callback returns. Exposure requires a wolfSSL-backed application that enables CA caching, replaces the store in CURLOPT_SSL_CTX_FUNCTION, and connects through an attacker-controlled TLS endpoint.

The record

CVE
CVE-2026-82208
Published
Sep 6, 2026
Updated
Sep 8, 2026
Vendor
curl
Product
curl
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.10.0 <=8.10.0
  2. Affected versionversion=8.10.1 <=8.10.1
  3. Affected versionversion=8.11.0 <=8.11.0
  4. Affected versionversion=8.11.1 <=8.11.1
  5. Affected versionversion=8.12.0 <=8.12.0
  6. Affected versionversion=8.12.1 <=8.12.1
  7. Affected versionversion=8.13.0 <=8.13.0
  8. Affected versionversion=8.14.0 <=8.14.0
  9. Affected versionversion=8.14.1 <=8.14.1
  10. Affected versionversion=8.15.0 <=8.15.0
  11. Affected versionversion=8.16.0 <=8.16.0
  12. Affected versionversion=8.17.0 <=8.17.0
  13. Affected versionversion=8.18.0 <=8.18.0
  14. Affected versionversion=8.19.0 <=8.19.0
  15. Affected versionversion=8.20.0 <=8.20.0
  16. Affected versionversion=8.21.0 <=8.21.0
  17. Affected versionversion=8.9.1 <=8.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=8.10.0 <=8.10.0; version=8.10.1 <=8.10.1; version=8.11.0 <=8.11.0; version=8.11.1 <=8.11.1; version=8.12.0 <=8.12.0; version=8.12.1 <=8.12.1; version=8.13.0 <=8.13.0; version=8.14.0 <=8.14.0; version=8.14.1 <=8.14.1; version=8.15.0 <=8.15.0; version=8.16.0 <=8.16.0; version=8.17.0 <=8.17.0; version=8.18.0 <=8.18.0; version=8.19.0 <=8.19.0; version=8.20.0 <=8.20.0; version=8.21.0 <=8.21.0; version=8.9.1 <=8.9.1

Published CVSS scores

4.8Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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