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CVE-2026-123568VulnerabilityPublished

Sveltejs devalue before 5.6.3 contains a prototype pollution vulnerability that allows attackers to alter object

Source GCVE Database

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Authoritative record:CVE-2026-123568· Low 2.1

Not known to be exploited · CVSS 2.1 Low : upgrade to 5.6.3 when convenient.

Data as of 8 Nov 2026, 06:33 UTC

CVSS 4.0 base score
2.1Low
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.02.1
CNA (VulnCheck)CVSS 3.14.4
Patch
Available – fixed in 5.6.3
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  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), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.

What to do

Upgrade devalue to 5.6.3.

Affected software

ProductAffectedFixed in
sveltejsdevalueAffected
  • <5.6.3
Fixed in
  • 5.6.3
npmdevaluepkg:npm/devalueOther threatsAffected
  • <5.6.3
Fixed in
  • 5.6.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Since the vulnerability affects versions before 5.6.3, upgrading to version 5.6.3 or later is implied as the remediation. Users should apply this update once available.

Description

Sveltejs devalue versions before 5.6.3 contain a prototype pollution vulnerability. This flaw allows attackers to manipulate object prototypes by providing untrusted data to the uneval function. When the affected code evaluates this data, it results in objects with polluted prototypes, causing output data to differ in structure from the original input. The vulnerability has a medium severity rating with a CVSS score of 4.4.

References

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