Chrome: External Control of Assumed-Immutable Web Parameter
CVE-2026-8577 is a high-severity external control of assumed-immutable web parameter vulnerability in Chrome from Google, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 148.0.7778.168 as the first without the flaw, so updating Chrome to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Chrome to 148.0.7778.168 or a later version.
- Read the advisory on chromereleases.googleblog.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Chrome | 148.0.7778.168 up to, but not including, 148.0.7778.168 | 148.0.7778.168 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Integer overflow in Fonts in Google Chrome prior to 148.0.7778.168 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium security severity: Medium)
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: External Control of Assumed-Immutable Web Parameter
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.
How developers prevent this class of flaw
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More External Control of Assumed-Immutable Web Parameter vulnerabilities (CWE-472)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- issues.chromium.org/issues/496302307Permissions Required
Other vulnerabilities in Chrome
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent External Control of Assumed-Immutable Web Parameter vulnerabilities
- 8.3 High severity
- 8.3 High severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
- 8.8 High severity
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