How severe is CVE-2025-27088?

No CVSS score has been assigned to CVE-2025-27088 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-27088?

CVE-2025-27088 affects the following packages: github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy (Go). Ecosystems affected: Go.

How do I fix CVE-2025-27088?

Update github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy to 0.0.0-20250220214310-c611c741ed48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27088 is resolved across your whole dependency graph.

How do I detect CVE-2025-27088 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-27088 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-2025-27088?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-27088 can be triaged on real exposure rather than presence alone.

Is CVE-2025-27088 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-27088 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-2025-27088?

CVE-2025-27088 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th 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.

What type of vulnerability is CVE-2025-27088?

CVE-2025-27088 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-27088 published, and has it been updated?

CVE-2025-27088 was published on February 20, 2025 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-27088: s3-proxy XSS

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-27088.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% 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

🐹github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

oxyno-zeta/s3-proxy is an aws s3 proxy written in go. In affected versions a Reflected Cross-site Scripting (XSS) vulnerability enables attackers to create malicious URLs that, when visited, inject scripts into the web application. This can lead to session hijacking or phishing attacks on a trusted domain, posing a moderate risk to all users. It's possible to inject html elements, including scripts through the folder-list template. The affected template allows users to interact with the URL path provided by the Request.URL.Path variable, which is then rendered directly into the HTML without proper sanitization or escaping. This can be abused by attackers who craft a malicious URL containing injected HTML or JavaScript. When users visit such a URL, the malicious script will be executed in the user's context. This issue has been addressed in version 4.18.1 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy`	all versions	0.0.0-20250220214310-c611c741ed48`go get github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy@v0.0.0-20250220214310-c611c741ed48`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy to 0.0.0-20250220214310-c611c741ed48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27088 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-2025-27088 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2025-27088. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

oxyno-zeta/s3-proxy is an aws s3 proxy written in go. In affected versions a Reflected Cross-site Scripting (XSS) vulnerability enables attackers to create malicious URLs that, when visited, inject scripts into the web application. This can lead to session hijacking or phishing attacks on a trusted domain, posing a moderate risk to all users. It's possible to inject html elements, including scripts through the folder-list template. The affected template allows users to interact with the URL path provided by the `Request.URL.Path` variable, which is then rendered directly into the HTML without

O3 Security · Impact-Aware SCA

Is CVE-2025-27088 in your dependencies?

O3 Security finds CVE-2025-27088 across Go 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

CVE-2025-27088 — s3-proxy