CyberSecBulletin
CVE-2026-86145NVD status: Deferred

PCRE2: Improper Protection of Alternate Path

Published Updated By the CyberSecBulletin desk

CVE-2026-86145 is a high-severity improper protection of alternate path vulnerability in PCRE2 from PCRE, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 10.48 as the first without the flaw, so updating PCRE2 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update PCRE2 to 10.48 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
PCREPCRE210.32 up to, but not including, 10.4810.48

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
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
HighData or code can be modified at will.
Availability
LowPerformance or availability is reduced.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L. Scored by CNA (mitre.org).

Official description

PCRE2 before 10.48 allows a pcre2_dfa_match out-of-bounds write because reuse of a cached workspace block, in a recursive DFA matching workspace, lacks a size check (even though a newly allocated block, for the same purpose, does have a size check). This outcome requires an attacker-controlled regular expression, or a recursive pattern in conjunction with a small heap limit (this can be set through the API).

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Protection of Alternate Path

The product does not sufficiently protect all possible paths that a user can take to access restricted functionality or resources.

How developers prevent this class of flaw

  • Deploy different layers of protection to implement security in depth.

More Improper Protection of Alternate Path vulnerabilities (CWE-424)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in PCRE2

All PCRE2 vulnerabilities

Recent Improper Protection of Alternate Path vulnerabilities

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