Is CVE-2025-21617 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-21617 being exploited in the wild.

How severe is CVE-2025-21617?

Medium severity, with a CVSS score of 4, published 6 January 2025.

Which products and versions are affected?

Guzzle Oauth-Subscriber < 0.8.1; guzzlehttp/oauth-subscriber (Packagist) < 0.8.1, ECOSYSTEM:introduced=0,fixed=0.8.1.

Is there a fix for CVE-2025-21617?

Yes. guzzlehttp/oauth-subscriber (Packagist): upgrade to 0.8.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2025-21617 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2025-21617?

Check whether you run Guzzle Oauth-Subscriber or guzzlehttp/oauth-subscriber (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2025-21617: Guzzle OAuth Subscriber weak PRNG in nonce generation

Q: Is there a fix for CVE-2025-21617?

Yes. guzzlehttp/oauth-subscriber (Packagist): upgrade to 0.8.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2025-21617 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2025-21617?

Check whether you run Guzzle Oauth-Subscriber or guzzlehttp/oauth-subscriber (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2025-21617 · Severity: medium · CVSS 4 · Published 2025-01-06

Guzzle OAuth Subscriber is a software library used to handle authentication for web requests. A security flaw was found where the library generates predictable security tokens (nonces), which could allow an attacker to intercept and reuse legitimate requests if the connection is not encrypted with TLS. This could lead to unauthorized actions or data exposure depending on the specific application implementation.

Vendors: Guzzle, Packagist.

Quick answers

Is CVE-2025-21617 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-21617 being exploited in the wild.
How severe is CVE-2025-21617?: Medium severity, with a CVSS score of 4, published 6 January 2025.
Which products and versions are affected?: Guzzle Oauth-Subscriber < 0.8.1; guzzlehttp/oauth-subscriber (Packagist) < 0.8.1, ECOSYSTEM:introduced=0,fixed=0.8.1.
Is there a fix for CVE-2025-21617?: Yes. guzzlehttp/oauth-subscriber (Packagist): upgrade to 0.8.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-21617 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2025-21617?: Check whether you run Guzzle Oauth-Subscriber or guzzlehttp/oauth-subscriber (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

guzzlehttp/oauth-subscriber (Packagist): upgrade to 0.8.1 or later
```
composer require guzzlehttp/oauth-subscriber:^0.8.1
```

Technical details

The vulnerability is classified as a Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (CWE-338) within the Oauth1.php component of the Guzzle OAuth Subscriber library. The nonce generation process lacks sufficient entropy, making the resulting values predictable. An attacker could exploit this to perform replay attacks against servers, particularly in environments where TLS is not enforced. The issue is addressed in version 0.8.1 by implementing a more secure random source.

Affected products

Guzzle oauth-subscriber < 0.8.1

Identifiers

CVE-2025-21617
GHSA-237r-r8m4-4q88

Timeline

2025-01-06: advisory: GitHub Advisory published
2025-01-06: patched: Version 0.8.1 released

References

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