NVD / CVE Program· CNA GitHub_M

CVE-2026-55497: Cloudreve: Server crash through image decompression/pixel bomb in thumbnail & avatar decoding (DoS)

MediumCVSS 6.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.53% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: cloudreve cloudreve 4.17.0.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to cloudreve cloudreve 4.17.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Cloudreve is a self-hosted file management and sharing system. Prior to 4.17.0, the built-in thumbnail and avatar image decoders limit compressed file size but do not limit decoded pixel dimensions, allowing an authenticated user to submit a small PNG, JPEG, or GIF that triggers an unbounded allocation and terminates the Cloudreve process through fatal out-of-memory behavior. This issue is fixed in version 4.17.0.

Denial of service

Published: Jul 31, 2026
Updated: Sep 8, 2026
EPSS: 0.5% · 45th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 26 / 40 · 6.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.5%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 6.5; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

cloudreve cloudreve
- < 4.17.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Go	github.com/cloudreve/Cloudreve	from 0	—
Go	github.com/cloudreve/Cloudreve/v3	from 0	—
Go	github.com/cloudreve/Cloudreve/v3	up to and including 3.0.0-20250225100611-da4e44b77af4	—
Go	github.com/cloudreve/Cloudreve/v4	before 4.0.0-20260613024411-3607f79bb44c	4.0.0-20260613024411-3607f79bb44c

Same product

cloudreve: all records

Other highest-scoring records for the same primary product.

CVE-2026-25726Cloudreve is vulnerable to Account Takeover via Weak Cryptographic Token Generation (Insecure PRNG Seeding)
39Monitor
CVE-2026-54560Cloudreve: OAuth access tokens bypass scope enforcement due to missing client_id claim
30Monitor
CVE-2026-77633Cloudreve: Storage-quota TOCTOU race allows quota bypass and storage-based denial of service
28Monitor

Published before and after this one in the same product

← EarlierCVE-2026-55495Jul 31, 2026 · Cloudreve: Path Traversal in WOPI PUT_RELATIVE Allows Arbitrary File Creation in Owner Account
17Monitor
← EarlierCVE-2026-55496Jul 31, 2026 · Cloudreve: Inactive/banned account emails leaked via GET /api/v4/user/search because SearchActive() omits the active-status predicate
17Monitor
Later →CVE-2026-55499Jul 31, 2026 · Cloudreve: Broken access control in file event stream leaks activity events for unshared siblings to single-file share recipients
17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
cloudreve cloudreve	4.17.0 · description	Vendor (CNA)
Go:github.com/cloudreve/Cloudreve/v4	4.0.0-20260613024411-3607f79bb44c	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

cloudreve/cloudrevecommit 3607f79

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0710 · Jul 31, 2026(Cloudreve Güvenlik Zafiyeti)

All national notices →

Not on record for this CVE: researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/cloudreve/cloudreve/commit/3607f79bb44c35d0be4fa8b6e24c0502b51415a9

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records