CVE-2026-42175 is a medium-severity (CVSS 6.5) Server-Side Request Forgery (SSRF) vulnerability in requests-hardened. A fix is available for requests-hardened — see the affected versions and patch details below.
requests-hardened: Server-Side Request Forgery (SSRF) in requests-hardened RFC 6598
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42175.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
requests-hardenedReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
The SSRF protection in requests-hardened prior to version 1.2.1 fails to block IP addresses within the RFC 6598 Shared Address Space (100.64.0.0/10). An attacker who can supply arbitrary URLs to requests-hardened could exploit this gap to access internal services hosted within 100.64.0.0/10. This is for example relevant in environments such as AWS EKS where 100.64.0.0/10 is commonly used as the default pod CIDR.
The impact is environment-dependent, deployments that utilize the affected CIDR range for internal networking are exposed to SSRF bypass, while others may not be affected.
The issue is resolved in version 1.2.1 by extending the IP filtering logic to explicitly block the RFC 6598 range in addition to standard private addresses, as well as blocking all other reserved addresses (such as multicast) to prevent the re-occurrence of similar issues.
Version 1.2.1 is now blocking the following CIDRs:
192.88.99.0/24- 6to4 relay anycast100.64.0.0/10- CG-NAT5f00::/16- IPv6 Segment Routing64:ff9b::/96- used for IPv6 & IPv4 translation (NAT64)2001:20::/28- ORCHIDv2 (overlay identifiers)224.0.0.0/4- multicastff00::/8- multicast
Resources
- https://github.com/python/cpython/issues/119812
- https://github.com/saleor/requests-hardened/commit/b7403f88d3b3689e57435b75b51691a160aaeef5 - the fix itself
- https://github.com/saleor/requests-hardened/commit/a266b3958bb142bca515b3c230fdea19fbda327c - follow up, adding additional support for outdated Python versions (
3.11.9and3.10.11instead of only3.11.15and3.10.20) - https://github.com/saleor/requests-hardened/releases/tag/v1.2.1
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | requests-hardened | all versions | 1.2.1pip install --upgrade 'requests-hardened==1.2.1' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for requests-hardened, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update requests-hardened to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42175 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.
Frequently Asked Questions
Is CVE-2026-42175 in your dependencies?
Find it across PyPI, including transitive dependencies.