CVE-2025-55303
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Unauthorized third-party images in Astro’s _image endpoint
rank 19 = 0 + 15 + 0 + 4 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00637 · without this subject the record ranks 19
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 6.1, from NVD · without this subject the record ranks 4
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 19
How much of the world it touches
NVD CPE configurations
2 products in the CPE ranges · without this subject the record ranks 15
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 19
under $1 = $4.99M incident cost x 0 exposure x 0.00637 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
This record is one instance of CWE-79, improper neutralization of input during web page generation ('cross-site scripting'). The index holds 47894 prior instances of this class, 32 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
Sources disagree here.
Both shown, dated. We don't pick winners. disagreement-rules@v1
Running withastro astro? Check your version
A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.
Watch this record
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Record your call
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Harm, if it fires from the vector and the weakness
Written for the ticket you're about to file.
CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
Astro is a web framework for content-driven websites. In versions of astro before 5.13.2 and 4.16.18, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served. On-demand rendered sites built with Astro include an /_image endpoint which returns optimized versions of images. A bug in impacted versions of astro allows an attacker to bypass the third-party domain restrictions by using a protocol-relative URL as the image source, e.g. /_image?href=//example.com/image.png. This vulnerability is fixed in 5.13.2 and 4.16.18. receipt
NVD's analysis a second authority
- severity
- 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- weakness
- CWE-79; CWE-115
- affected versions
- astro < 4.16.18; astro >= 5.0.0 < 5.13.2
- also scored by
- [email protected] 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
The CNA scored it 6.9 and NVD 6.1. Both are shown because both were published; we do not pick one.
check it yourself github.com github.com receipt
Movement the material steps
Show all 20 observations
20 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 11 months when this index was last written.
The pattern, elsewhere
This record is one instance of CWE-79, improper neutralization of input during web page generation ('cross-site scripting'). The index holds 47894 prior instances of this class, 32 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
47894 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
Siblings and hubs
Records related to this one
No record cites this identifier and it carries no alias. Its defect family is below.
Its defect family
withastro astro
Of the 10 records in this family that state one, this holds the highest EPSS percentile: 0.48152.
Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.
Family membership: held values
This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.
Browse the index from here
These are index-wide views, not findings about CVE-2025-55303.
What usually comes next
Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.