CVE-2026-42570: sveltejs devalue · Unthrottled Resource Allocation
Affects sveltejs devalueSource CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade to 5.8.1 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.8.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 9 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade sveltejs devalue to 5.8.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| sveltejsdevalue | Affected
| Fixed in
|
npmdevaluepkg:npm/devalueOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in sveltejs devalue version 5.8.1. Users should upgrade to version 5.8.1 or later to remediate this vulnerability. The Red Hat advisory confirms the issue and the availability of a patch. No additional mitigation steps are indicated or required beyond applying the official fix.
Description
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate much more memory than was needed when deserializing sparse arrays, leading to excessive memory consumption. This issue has been patched in version 5.8.1.
References
- github.com/sveltejs/devalue/security/advisories/GHSA-77vg-94rm-hx3p (opens in a new tab)
- github.com/sveltejs/devalue/commit/206ca6712fbc380a4571c59de9ab04b91110792d (opens in a new tab)
- github.com/sveltejs/devalue/releases/tag/v5.8.1 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-42570 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2487050 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42570.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37272 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:57590 (opens in a new tab)