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VulnerabilityPublished

CVE-2026-33769: withastro astro · Improper Input Validation

Affects withastro astroSource CVE Database V5

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Public exploit available · CVSS 2.9 Low : upgrade to 5.18.1 as a priority.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
2.9Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.18.1
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CVSS exploit maturity: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade withastro astro to 5.18.1.

Affected software

ProductAffectedFixed in
withastroastroAffected
  • >=2.10.10 <5.18.1
Fixed in
  • 5.18.1

AI-suggested

Organizations should upgrade the Astro framework to version 5.18.1 or later, where the vulnerability is patched with corrected path matching logic. Until upgrading, administrators should review and tighten remotePatterns configurations to avoid using unanchored wildcards like /* and prefer explicit, anchored path prefixes. Implement additional access controls on server-side fetchers to restrict which remote hosts and paths can be accessed. Employ network-level controls such as firewalls or reverse proxies to limit external access to the vulnerable endpoints. Conduct thorough code reviews and penetration testing focused on path traversal and input validation in server-side fetchers. Monitor logs for unusual fetch requests that may indicate attempts to exploit this vulnerability. Finally, maintain an up-to-date inventory of Astro versions in use to ensure timely patching.

Description

CVE-2026-33769 is a low-severity vulnerability in the Astro web framework versions 2.10.10 up to but not including 5.18.1. It involves improper input validation in the remotePatterns path enforcement used by server-side fetchers like the image optimization endpoint. The flaw arises because the path matching logic for /* wildcards is unanchored, allowing attackers to craft pathnames that bypass intended allowlist prefixes and fetch resources outside the allowed scope on permitted hosts. This can lead to unauthorized data retrieval from the server. The vulnerability requires no authentication or user interaction and has not been observed exploited in the wild. It was patched in Astro version 5.

References

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