Devalue 5.8.0 before 5.9.3 Denial of Service via stringifyAsync Unhandled Rejection
devalue 5.8.0 through 5.9.2 is affected when serializing multiple promises with stringifyAsync under Node.js default unhandled-rejection behavior. Fixed in 5.9.3.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 5.9.3
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 5.9.3.
- Published
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 46/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
devalue (sveltejs/devalue) 5.8.0 before 5.9.3 contains an unhandled promise rejection in stringifyAsync: when serializing multiple promises, a later promise rejecting before an earlier one settles leaves an internal rejection unhandled, even if the caller catches the returned promise. An attacker able to influence the timing or failure of serialized asynchronous values can terminate the Node.js process.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach20/20devalue: 24.5M downloads a week
- Severity8.7/10CVSS 8.7
- No patch0/5No signal
What would change the score
- Would score about 91 if added to CISA KEV
- Would score about 86 if CISA's SSVC rates exploitation active
- Would score about 51 if advisories confirm default setups are exposed
Impact
What to do
Upgrade to a fixed version: 5.9.3.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- sveltejs devalue
From 5.8.0 · fixed in 5.9.3
- devaluenpm
From 5.8.0 · fixed in 5.9.3
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123562
Is CVE-2026-123562 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When multiple promises are serialized, a later promise can reject before an earlier one settles. Under Node.js default unhandled-rejection behavior, this can terminate the Node.js process, causing denial of service.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-123562?
devalue: from 5.8.0 before 5.9.3. devalue (npm): from 5.8.0 before 5.9.3.Source: cve.now feed data
Am I affected, and how do I check?
Versions 5.8.0 through 5.9.2 of devalue are affected, and the bug involves serializing multiple promises under Node.js default unhandled-rejection behavior. The installed version can be checked with npm ls devalue.Source: github.com, vulncheck.com
How do I fix CVE-2026-123562?
Upgrade devalue to 5.9.3, which contains the fix.Source: github.com, vulncheck.com