CVE-2026-49457: Quic QUIC Has Broken TLS Verification Vulnerability

CRITICAL
Advisory Identifier: GHSA-2r8v-p65x-3663
Share
CVSS 9.1
CWE-295 CWE-297
Published
Advisory Summary

CVE-2026-49457 is a CRITICAL (CVSS 9.1) quic has broken tls verification vulnerability (CWE-295: Improper Certificate Validation) affecting Quic libraries in the Hex ecosystem. The issue involves quic has broken tls verification. Remediation is available by upgrading affected packages to version 1.4.4.

CVE-2026-49457 at a Glance

CVE Identifier CVE-2026-49457
GHSA Identifier GHSA-2r8v-p65x-3663
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-295: Improper Certificate Validation
Affected Product Quic
Package Ecosystem Hex
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-49457

To remediate this vulnerability, upgrade all affected Quic dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

quic fixed: 1.4.4 
Upgrade quic to 1.4.4
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for quic

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-49457, inspect your project dependencies for Quic:

inspect dependencies for quic

Analyze the terminal output to locate any version of Quic in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.4.4), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-295: Improper Certificate Validation, where the product does not validate, or incorrectly validates, a certificate. In Quic, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact The QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so `verify` was effectively a no-op on the client. A man-in-the-middle on the network path could present any certificate and impersonate any server, defeating the confidentiality and integrity of the connection. HTTP/3 uses the same client and was equally affected. Handshakes authenticated by a PSK (session resumption) are not affected, because the peer is authenticated by the PSK binder and no certificate is sent. ### Patches Fixed in 1.4.4. The client now verifies the CertificateVerify signature, validates the certificate chain against the trust store (`cacerts` option, the operating system store by default), and checks the hostname. Client `verify` now defaults to on; set `verify => false` to accept any certificate (for example a self-signed test server). ### Workarounds None before 1.4.4. `verify => true` had no effect, and inspecting the certificate after connecting does not help because without the signature check the peer is never proven to own the certificate it presents. ### Credit Reported by benmmurphy.

CVE-2026-49457 Affected Quic Versions

1 component(s)
Fixed Versions:
1.4.4
Product / Package Ecosystem Affected Versions Fixed Version
quic
 Hex
< 1.4.4
1.4.4

References

GitHub Advisory / Wiki ADVISORY
https://github.com/benoitc/erlang_quic/security/advisories/GHSA-2r8v-p65x-3663
Quic Source Repository REPOSITORY
https://github.com/benoitc/erlang_quic

Frequently Asked Questions

What is CVE-2026-49457?
CVE-2026-49457 is a security vulnerability in Quic involving QUIC has Broken TLS verification under CWE-295: Improper Certificate Validation.
Which Quic versions are affected?
Affected versions include releases prior to 1.4.4 across affected packages: quic.
What version fixes CVE-2026-49457?
Upgrading to 1.4.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is quic affected?
Yes, quic is affected in releases prior to 1.4.4. Upgrade your dependency to 1.4.4 or later.
What is the CVSS score of CVE-2026-49457?
CVE-2026-49457 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-49457?
CVE-2026-49457 is classified under CWE-295: Improper Certificate Validation (The product does not validate, or incorrectly validates, a certificate.).
How can I check Hex dependencies for CVE-2026-49457?
Run the dependency tree command: 'inspect dependencies for quic'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2r8v-p65x-3663",
  "modified" : "2026-07-01T20:32:34Z",
  "published" : "2026-07-01T20:32:34Z",
  "aliases" : [ "CVE-2026-49457" ],
  "summary" : "QUIC has Broken TLS verification",
  "details" : "### Impact\n\nThe QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so `verify` was effectively a no-op on the client. A man-in-the-middle on the network path could present any certificate and impersonate any server, defeating the confidentiality and integrity of the connection. HTTP/3 uses the same client and was equally affected. Handshakes authenticated by a PSK (session resumption) are not affected, because the peer is authenticated by the PSK binder and no certificate is sent.\n\n### Patches\n\nFixed in 1.4.4. The client now verifies the CertificateVerify signature, validates the certificate chain against the trust store (`cacerts` option, the operating system store by default), and checks the hostname. Client `verify` now defaults to on; set `verify => false` to accept any certificate (for example a self-signed test server).\n\n### Workarounds\n\nNone before 1.4.4. `verify => true` had no effect, and inspecting the certificate after connecting does not help because without the signature check the peer is never proven to own the certificate it presents.\n\n### Credit\n\nReported by benmmurphy.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Hex",
      "name" : "quic"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.4.4"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.4.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/benoitc/erlang_quic/security/advisories/GHSA-2r8v-p65x-3663"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/benoitc/erlang_quic"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-295", "CWE-297" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-01T20:32:34Z",
    "nvd_published_at" : null
  }
}