CVE-2026-27125
Svelte SSR attribute spreading includes inherited properties from prototype chain
svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
5.3
Svelte SSR attribute spreading includes inherited properties from prototype chain
svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
- Record
CVE-2026-27125- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-915
- Updated
- 2026-11-02
EUVDEUVD-2026-7765
5.3
svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
- Record
EUVD-2026-7765- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-crpf-4hrx-3jrp
5.3
Svelte SSR attribute spreading includes inherited properties from prototype chain
In server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.
- Record
GHSA-crpf-4hrx-3jrp- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-915
- Updated
- 2026-11-02
NVD
5.3
svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
- Record
CVE-2026-27125- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/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 - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-915
- Updated
- 2026-11-02
OSV
5.3
Svelte SSR attribute spreading includes inherited properties from prototype chain
svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
- Record
CVE-2026-27125- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-915
- Updated
- 2026-11-02
OSVGHSA-crpf-4hrx-3jrp
5.3
Svelte SSR attribute spreading includes inherited properties from prototype chain
In server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.
- Record
GHSA-crpf-4hrx-3jrp- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-915
- Updated
- 2026-11-02
Show 5 moreShow less
OSVCLSA-2026-1775953999 No score
TuxCare security update for svelte (4 CVEs)
TuxCare rebuilt svelte to address 4 CVEs. Fixed in 4.2.20-tuxcare.1.
- Record
CLSA-2026-1775953999- Updated
- 2026-11-02
OSVCLSA-2026-1776040402 No score
TuxCare security update for svelte (5 CVEs)
TuxCare rebuilt svelte to address 5 CVEs. Fixed in 3.59.2-tuxcare.1.
- Record
CLSA-2026-1776040402- Updated
- 2026-11-02
OSVCLSA-2026-1776126838 No score
TuxCare security update for svelte (6 CVEs)
TuxCare rebuilt svelte to address 6 CVEs. Fixed in 2.16.1-tuxcare.1.
- Record
CLSA-2026-1776126838- Updated
- 2026-11-02
OSVCLSA-2026-1776213244 No score
TuxCare security update for svelte (6 CVEs)
TuxCare rebuilt svelte to address 6 CVEs. Fixed in 1.64.1-tuxcare.1.
- Record
CLSA-2026-1776213244- Updated
- 2026-11-02
OSVCLSA-2026-1776213252 No score
TuxCare security update for svelte (6 CVEs)
TuxCare rebuilt svelte to address 6 CVEs. Fixed in 0.3.0-tuxcare.1.
- Record
CLSA-2026-1776213252- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
sveltenpm |
through 5.51.4 | 5.51.5 |
svelteTuxCare:npm From an advisory covering 4 CVEs |
4.2.20-tuxcare.0 up to 4.2.20-tuxcare.1, plus listed versions 4.2.20 |
4.2.20-tuxcare.1 |
svelteTuxCare:npm From an advisory covering 5 CVEs |
3.59.2-tuxcare.0 up to 3.59.2-tuxcare.1, plus listed versions 3.59.2 |
3.59.2-tuxcare.1 |
svelteTuxCare:npm From an advisory covering 6 CVEs |
2.16.1-tuxcare.0 up to 2.16.1-tuxcare.1, plus listed versions 2.16.1 |
2.16.1-tuxcare.1 |
svelteTuxCare:npm From an advisory covering 6 CVEs |
1.64.1-tuxcare.0 up to 1.64.1-tuxcare.1, plus listed versions 1.64.1 |
1.64.1-tuxcare.1 |
svelteTuxCare:npm From an advisory covering 6 CVEs |
0.3.0-tuxcare.0 up to 0.3.0-tuxcare.1, plus listed versions 0.3.0 |
0.3.0-tuxcare.1 |
sveltenpm |
before 5.51.5 | 5.51.5 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-27125 is a medium vulnerability (CVSS 5.3) in Svelte, published February 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in svelte 5.51.5.
References
github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp
github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f
github.com/sveltejs/svelte/releases/tag/[email protected]
nvd.nist.gov/vuln/detail/CVE-2026-27125
github.com/advisories/GHSA-crpf-4hrx-3jrp
github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27125.json
github.com/sveltejs/svelte