How severe is CVE-2024-56159?

No CVSS score has been assigned to CVE-2024-56159 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-56159?

CVE-2024-56159 affects the following packages: astro (npm), astro (npm). Ecosystems affected: npm.

How do I fix CVE-2024-56159?

Update astro to 5.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56159 is resolved across your whole dependency graph.

How do I detect CVE-2024-56159 in my npm dependencies?

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

How do I mitigate CVE-2024-56159 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-2024-56159?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-56159 can be triaged on real exposure rather than presence alone.

Is CVE-2024-56159 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-56159 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-2024-56159?

CVE-2024-56159 has an EPSS (Exploit Prediction Scoring System) score of 1.5%, placing it in the 73th 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-2024-56159?

CVE-2024-56159 is classified as CWE-219 (CWE-219). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2024-56159?

A Nuclei detection template exists for CVE-2024-56159, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2024-56159 published, and has it been updated?

CVE-2024-56159 was published on December 19, 2024 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.

📦 npm

Not in CISA KEV

CVE-2024-56159 — astro

Fix: withastro/astro@039d022

CVE-2024-56159 is a CWE-219 vulnerability in astro. A fix is available for astro — see the affected versions and patch details below.

Server source code is exposed to the public if sourcemaps are enabled

Also known asGHSA-49w6-73cw-chjr

Published

Dec 19, 2024

Updated

Aug 12, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-56159.

EPSS Exploitation Probability

via FIRST.org ↗

1.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs73th percentile — riskier than 73% 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

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

694other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

astronpm

4.2Mdownloads / week

Description

Summary

A bug in the build process allows any unauthenticated user to read parts of the server source code.

Details

During build, along with client assets such as css and font files, the sourcemap files for the server code are moved to a publicly-accessible folder. https://github.com/withastro/astro/blob/176fe9f113fd912f9b61e848b00bbcfecd6d5c2c/packages/astro/src/core/build/static-build.ts#L139

Any outside party can read them with an unauthorized HTTP GET request to the same server hosting the rest of the website.

While some server files are hashed, making their access obscure, the files corresponding to the file system router (those in src/pages) are predictably named. For example. the sourcemap file for src/pages/index.astro gets named dist/client/pages/index.astro.mjs.map.

PoC

Here is one example of an affected open-source website: https://creatorsgarten.org/pages/index.astro.mjs.map

The file can be saved and opened using https://evanw.github.io/source-map-visualization/ to reconstruct the source code.

The above accurately mirrors the source code as seen in the repository: https://github.com/creatorsgarten/creatorsgarten.org/blob/main/src/pages/index.astro

The above was found as the 4th result (and the first one on Astro 5.0+) when making the following search query on GitHub.com (search results link):

path:astro.config.mjs @sentry/astro

This vulnerability is the root cause of https://github.com/withastro/astro/issues/12703, which links to a simple stackblitz project demonstrating the vulnerability. Upon build, notice the contents of the dist/client (referred to as config.build.client in astro code) folder. All astro servers make the folder in question accessible to the public internet without any authentication. It contains .map files corresponding to the code that runs on the server.

Impact

All server-output (SSR) projects on Astro 5 versions v5.0.3 through v5.0.6 (inclusive), that have sourcemaps enabled, either directly or through an add-on such as sentry, are affected. The fix for server-output projects was released in [email protected].

Additionally, all static-output (SSG) projects built using Astro 4 versions 4.16.17 or older, or Astro 5 versions 5.0.7 or older, that have sourcemaps enabled are also affected. The fix for static-output projects was released in [email protected], and backported to Astro v4 in [email protected].

The immediate impact is limited to source code. Any secrets or environment variables are not exposed unless they are present verbatim in the source code.

There is no immediate loss of integrity within the the vulnerable server. However, it is possible to subsequently discover another vulnerability via the revealed source code .

There is no immediate impact to availability of the vulnerable server. However, the presence of an unsafe regular expression, for example, can quickly be exploited to subsequently compromise the availability.

Network attack vector.
Low attack complexity.
No privileges required.
No interaction required from an authorized user.
Scope is limited to first party. Although the source code of closed-source third-party software may also be exposed.

Remediation

The fix for server-output projects was released in [email protected], and the fix for static-output projects was released in [email protected] and backported to Astro v4 in [email protected]. Users are advised to update immediately if they are using sourcemaps or an integration that enables sourcemaps.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`astro`	≥ 5.0.0-alpha.0&&< 5.0.8	5.0.8`npm install astro@5.0.8`
📦npm	`astro`	all versions	4.16.18`npm install astro@4.16.18`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for astro, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update astro to 5.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56159 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-2024-56159 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2024-56159. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

How to detect CVE-2024-56159

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2024-56159 -u https://target

Template: Astro - Information Disclosure
Severity: medium
Impact: Unauthenticated users can access server source code, potentially leading to discovery of further vulnerabilities or sensitive information.
Remediation: Update Astro to version 5.0.8 or later for server-output projects, and to 5.0.9 or later (or 4.16.18 for Astro v4) for static-output projects with sourcemaps enabled.

Template by ProjectDiscovery nuclei-templates (theamanrawat), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

### Summary A bug in the build process allows any unauthenticated user to read parts of the server source code. ### Details During build, along with client assets such as css and font files, the sourcemap files **for the server code** are moved to a publicly-accessible folder. https://github.com/withastro/astro/blob/176fe9f113fd912f9b61e848b00bbcfecd6d5c2c/packages/astro/src/core/build/static-build.ts#L139 Any outside party can read them with an unauthorized HTTP GET request to the same server hosting the rest of the website. While some server files are hashed, making their access obscure,

O3 Security · Impact-Aware SCA

Is CVE-2024-56159 in your dependencies?

O3 Security finds CVE-2024-56159 across npm 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