CVE-2023-49277 is a high-severity (CVSS 8.3) Cross-site Scripting (XSS) vulnerability in dpaste. A fix is available for dpaste — see the affected versions and patch details below.
Reflected Cross-site Scripting Vulnerability in dpaste
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-2023-49277.
EPSS Exploitation Probability
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.
How urgent is this, really
CVE-2023-49277 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
dpasteReal-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
Impact
A security vulnerability has been identified in the expires parameter of the dpaste API, allowing for a POST Reflected XSS attack. This vulnerability can be exploited by an attacker to execute arbitrary JavaScript code in the context of a user's browser, potentially leading to unauthorized access, data theft, or other malicious activities.
Patches
- A patch has been applied to the dpaste GitHub repository to address the specific content value injection vulnerability.
- Users are strongly advised to upgrade to dpaste release v3.8 or later versions, as dpaste versions older than v3.8 are susceptible to the identified security vulnerability.
- The patch can be viewed and applied from the following link: dpaste Commit Patch
Workarounds
At this time, the recommended course of action is to apply the provided patch to the affected systems. No known workarounds have been identified, and applying the patch is the most effective way to remediate the vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | dpaste | all versions | 3.8pip install --upgrade 'dpaste==3.8' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dpaste, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update dpaste to 3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49277 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-2023-49277 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-49277. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-49277 in your dependencies?
O3 Security finds CVE-2023-49277 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.