CVE-2026-78903
Description revised (poc_count, poc_public, poc_url). The record changed; nothing in the observed threat did.
CVE record, CISA KEV and EPSS as of 2026-10-18.
CVEs like this one computed, by meaning
What to do now held facts and links
- Upgrade to 152.0.7977.65 or later CVE record
- Record your decision, dated and frozen with today's evidence: patch by a date · mitigated by a compensating control · deferred · accepted the risk · not affected
- Check your version against the ranges this record publishes.
What it is stated by the CNA
Incomplete cleanup in SiteIsolation in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: Medium)
- weakness
- CWE-459 Incomplete cleanup
- affected
- Google Chrome
- published ranges
- google chrome < 152.0.7977.65
- fixed in
- 152.0.7977.65
- assigned by
- Chrome
- published
- 2026-08-25
Exploit code held, dated
- exploit code
- 1 public proof-of-concept repository, first seen 2026-08-30 (PoC-in-GitHub).
What moved held, dated
| date | EPSS | event |
|---|---|---|
| 28 Aug 2026 | 0.00277 | |
| 29 Aug 2026 | 0.00268 | |
| 28 Sep 2026 | 0.00295 |
3 observations held. A step marked with a scoring model moved because the measurement was replaced, not because the vulnerability changed.
Outside the record researched, cited
This section reads the record's references and adds cited findings from outside it. It needs an account. Everything above is held facts and is complete without it.
What would change this brief held, dated
- CISA KEV
- Not listed in the catalogue we hold. A listing changes this brief.
- exploit probability
- 0.00 on 2026-09-28 (FIRST's EPSS, a probability and not evidence of exploitation). Next band line: 10% (0.10). Crossing a line changes this brief.
- fix
- Held: 152.0.7977.65. A newer fix from the CNA or OSV changes this brief.
How to check this
Every value above is held with two dates: when it was true upstream (as_of) and when we recorded it (tx_from). Re-derive the exploit probability as it stood on any date:
SELECT value, source, source_version, as_of, tx_from
FROM volatile_valid_as_of('CVE-2026-78903', '2026-10-31T23:59:59.999999Z', now());