CVE-2026-53431
Boruta accepts expired JWT client assertions due to missing exp claim validation
Description
Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired. Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges. This issue affects boruta: from 2.3.0 before 2.3.7.
INFO
Published Date :
July 30, 2026, 3:16 p.m.
Last Modified :
July 30, 2026, 5 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Affected Products
The following products are affected by CVE-2026-53431
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | CRITICAL | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | CRITICAL | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update Boruta to version 2.3.7 or later.
- Ensure JWT exp claims are always validated.
- Remove outdated JWT assertions.
- Monitor JWT usage and logging.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-53431.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-53431 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-53431
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-53431 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-53431 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jul. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:malach-it:boruta_auth:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/malach-it/boruta_auth', 'vendor': 'malach-it', 'modules': ["'Elixir.Boruta.Oauth.Request.Base'", "'Elixir.Boruta.Oauth.Authorization.Client.Token'"], 'product': 'boruta', 'versions': [{'status': 'affected', 'version': '2.3.0', 'lessThan': '2.3.7', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/boruta', 'packageName': 'boruta', 'programFiles': ['lib/boruta/oauth/request/base.ex', 'lib/boruta/oauth/authorization/client.ex'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Boruta.Oauth.Request.Base':fetch_client_authentication/1"}, {'name': "'Elixir.Boruta.Oauth.Request.Base':check_expiration/1"}, {'name': "'Elixir.Boruta.Oauth.Authorization.Client.Token':token_config/0"}]}, {'cpes': ['cpe:2.3:a:malach-it:boruta_auth:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/malach-it/boruta_auth', 'vendor': 'malach-it', 'modules': ["'Elixir.Boruta.Oauth.Request.Base'", "'Elixir.Boruta.Oauth.Authorization.Client.Token'"], 'product': 'boruta', 'versions': [{'status': 'affected', 'changes': [{'at': '5204f88f9b2cdd9637a755337ed5f99185be5474', 'status': 'unaffected'}, {'at': '69363432aa36760fc5438e4e17115d0f7c1b925a', 'status': 'unaffected'}], 'version': '5bfbe1c5443bffe71cf1bf954bbdff61327d9a83', 'lessThan': '*', 'versionType': 'git'}], 'packageURL': 'pkg:github/malach-it/boruta_auth', 'packageName': 'malach-it/boruta_auth', 'programFiles': ['lib/boruta/oauth/request/base.ex', 'lib/boruta/oauth/authorization/client.ex'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Boruta.Oauth.Request.Base':fetch_client_authentication/1"}, {'name': "'Elixir.Boruta.Oauth.Request.Base':check_expiration/1"}, {'name': "'Elixir.Boruta.Oauth.Authorization.Client.Token':token_config/0"}]}] Added Description Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired. Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges. This issue affects boruta: from 2.3.0 before 2.3.7. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-294 Added Reference https://cna.erlef.org/cves/CVE-2026-53431.html Added Reference https://github.com/malach-it/boruta_auth/commit/5204f88f9b2cdd9637a755337ed5f99185be5474 Added Reference https://github.com/malach-it/boruta_auth/commit/69363432aa36760fc5438e4e17115d0f7c1b925a Added Reference https://github.com/malach-it/boruta_auth/security/advisories/GHSA-xjv8-vmh5-xhf6 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-53431