Multiple vulnerabilities in urllib3



Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2025-66471
CVE-2025-66418
CWE-ID CWE-400
CWE-770
Exploitation vector Network
Public exploit N/A
Vulnerable software
 urllib3
Other software / Other software solutions

Vendor shazow (Andrey Petrov)

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Resource exhaustion

EUVDB-ID: #VU119231

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-66471

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the streaming API does not properly control consumption of internal resources. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

urllib3: 1.0 - 2.5.0

CPE2.3 External links

https://github.com/urllib3/urllib3/security/advisories/GHSA-2xpw-w6gg-jr37


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Allocation of Resources Without Limits or Throttling

EUVDB-ID: #VU119230

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-66418

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to missing limits on the number of links in the decompression chain when handling gzip or zstd data in the server response. A malicious server can send a response with a large amount of links and cause high CPU load, leading to a denial of service condition. 

Mitigation

Install updates from vendor's website.

Vulnerable software versions

urllib3: 1.24 - 2.5.0

CPE2.3 External links

https://github.com/urllib3/urllib3/security/advisories/GHSA-gm62-xv2j-4w53


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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