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CVE-2026-91831

LOW 3.8 PoC AVAILABLE

Published 2026-10-19 · Last modified 2026-10-19

The Subscribe to Comments WordPress plugin before 2.3.3 does not sanitise newline characters from a notification sender-name setting before using it in e-mail headers, allowing users with Author-level access and above to inject arbitrary e-mail headers, such as a hidden Bcc, and to spoof the sender.

EXPLOIT AVAILABLE

Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 5th percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

3.8CVSS 3.1 · LOW

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires an admin / high-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-91831/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-91831/poc.json

Affected

Vendors Unknown

Products Subscribe To Comments

Weakness (CWE)

  • CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

All CVSS metrics

  • LOW 3.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
  • LOW 3.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

References

Exploits & PoC

Sources: NVD · CVE.org · EPSS