CVE-2026-45077
Unauthenticated remote PHP deserialization in Symfony server:log allows RCE/DoS.
Is CVE-2026-45077 being exploited?
Not confirmed. CVE-2026-45077 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.67% probability of exploitation in the next 30 days.
How severe is CVE-2026-45077?
CVE-2026-45077 is rated High with a CVSS score of 8.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-45077?
Yes. A fix has been recorded for CVE-2026-45077. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-45077 affect?
CVE-2026-45077 affects Symfony <5.4.52, Symfony <6.4.40, Symfony <7.4.12, Symfony <8.0.12, and 2 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-45077?
Upgrade to 5.4.52/6.4.40/7.4.12/8.0.12 or disable/block server:log (port 9911).
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote PHP object deserialization via listener on 0.0.0.0:9911, enabling crash (DoS) and potential RCE via gadget chains.
Immediate action required
- affected< 5.4.52
- affected>= 6.0.0-BETA1 and < 6.4.40
- affected>= 7.0.0-BETA1 and < 7.4.12
- affected>= 8.0.0-BETA1 and < 8.0.12
- affected< 5.4.52
- affected>= 6.0.0-BETA1 and < 6.4.40
- affected>= 7.0.0-BETA1 and < 7.4.12
- affected>= 8.0.0-BETA1 and < 8.0.12
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.