How severe is CVE-2015-2296?

No CVSS score has been assigned to CVE-2015-2296 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2015-2296?

CVE-2015-2296 affects the following packages: requests (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2015-2296?

Update requests to 2.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-2296 is resolved across your whole dependency graph.

How do I detect CVE-2015-2296 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for requests, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2015-2296 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2015-2296?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2015-2296 can be triaged on real exposure rather than presence alone.

Is CVE-2015-2296 actively exploited in the wild?

No public exploit code has been indexed for CVE-2015-2296 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2015-2296?

CVE-2015-2296 has an EPSS (Exploit Prediction Scoring System) score of 3.4%, placing it in the 88th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2015-2296 published, and has it been updated?

CVE-2015-2296 was published on March 18, 2015 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2015-2296 — requests

Fix: kennethreitz/requests@3bd8afb

CVE-2015-2296 is a security vulnerability in requests. A fix is available for requests — see the affected versions and patch details below.

Python Requests Session Fixation

Also known asGHSA-pg2w-x9wp-vw92PYSEC-2015-17

Published

Mar 18, 2015

Updated

Apr 16, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs88th percentile — riskier than 88% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐍requests

Real-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 resolve_redirects function in sessions.py in requests 2.1.0 through 2.5.3 allows remote attackers to conduct session fixation attacks via a cookie without a host value in a redirect.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`requests`	≥ 2.1.0&&< 2.6.0	2.6.0`pip install --upgrade 'requests==2.6.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for requests, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update requests to 2.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-2296 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2015-2296 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2015-2296. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Ubuntu

USN-2531-1Ubuntu

Frequently Asked Questions

The resolve_redirects function in sessions.py in requests 2.1.0 through 2.5.3 allows remote attackers to conduct session fixation attacks via a cookie without a host value in a redirect.

O3 Security · Impact-Aware SCA

Is CVE-2015-2296 in your dependencies?

O3 Security finds CVE-2015-2296 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works