CVE-2025-62490
Use-after-free in js_print_object in QuickJS
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
8.8
Use-after-free in js_print_object in QuickJS
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
CVE-2025-62490- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L - Weakness
- CWE-416
- Updated
- 2026-11-02
EUVDEUVD-2025-34784
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
EUVD-2025-34784- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-g55w-pj8g-frvg
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array...
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
GHSA-g55w-pj8g-frvg- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
NVD
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
CVE-2025-62490- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSV
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
CVE-2025-62490- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2025-62490
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
DEBIAN-CVE-2025-62490- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-62490
8.8
In quickjs, in js_print_object, when printing an array, the function first fetches the array length and then loops over it. The issue is, printing a value is not side-effect free. An attacker-defined callback could run during js_print_value, during which the array could get resized and len1 become out of bounds. This results in a use-after-free.A second instance occurs in the same function during printing of a map or set objects. The code iterates over ms->records list, but once again, elements could be removed from the list during js_print_value call.
- Record
UBUNTU-CVE-2025-62490- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-06
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
quickjsDebian:13 |
All versions, plus listed versions 2025.04.26-1 |
None known |
quickjsDebian:14 |
All versions, plus listed versions 2025.04.26-1 |
None known |
quickjsUbuntu:25.10 |
All versions, plus listed versions 2024.01.13-52025.04.26-1 |
None known |
quickjsUbuntu:26.10 |
All versions, plus listed versions 2025.04.26-1build1 |
None known |
quickjsUbuntu:26.04:LTS |
All versions, plus listed versions 2025.04.26-12025.04.26-1build1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-62490 is a high vulnerability (CVSS 8.8) in Quickjs, published October 16, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. No source names a fixed version.