FedoraOperating system · Fedoraproject
CVE-2015-8386
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedPCRE before 8.38 mishandles the interaction of lookbehind assertions and mutually recursive subpatterns, which allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a crafted regular expression, as demonstrated by a JavaScript RegExp object encountered by Konqueror.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencePCRE library before version 8.38 contains a buffer overflow vulnerability when processing regular expressions that combine lookbehind assertions with mutually recursive subpatterns. Attackers can exploit this by providing crafted RegExp objects (as demonstrated in Konqueror) to cause denial of service or potentially achieve arbitrary code execution.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
FedoraOperating system
= 22
LinuxOperating system
= 7
PHPApplication
>= 5.5.0, < 5.5.32>= 5.6.0, < 5.6.18>= 7.0.0, < 7.0.3<= 8.37CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed PCRE library versionRun `pcre-config --version` or check the libpcre version file in `/usr/include/pcre.h` (look for PCRE_MAJOR and PCRE_MINOR macros)Affected if Version is 8.37 or earlier, or version cannot be determined and the library file modification date predates the 8.38 release (November 2015)
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Identify PHP version if in useRun `php -v` or check `phpinfo()` output to determine the PHP branch and exact version numberAffected if PHP version is 5.5.0 through 5.5.31, 5.6.0 through 5.6.17, or 7.0.0 through 7.0.2
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Check the operating system distribution and versionRun `cat /etc/fedora-release` for Fedora or `cat /etc/oracle-release` or `cat /etc/redhat-release` for Oracle LinuxAffected if Running Fedora 22 or Oracle Linux 7 with the vulnerable PCRE version still present
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Identify applications statically linked to PCRERun `ldd` on binary executables that process regular expressions (such as PHP, Apache with mod_php, or custom applications) and check if they link against a system PCRE library; for statically linked binaries, use `strings binary | grep -i pcre` or examine build configurationAffected if The application uses a PCRE library version 8.37 or earlier regardless of system PCRE version
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Verify if regex patterns with lookbehind assertions and recursive subpatterns are processedReview application code, configuration files, or user inputs that could provide regular expressions to the PCRE engine; specifically look for patterns using (?<=...) or (?<!...) followed by recursive pattern references like (?1) or (?R)Affected if The environment processes any regex patterns that combine lookbehind assertions with mutually recursive subpatterns, as this triggers the vulnerable code path
A system is affected if it runs PCRE version 8.37 or earlier, or PHP versions 5.5.0-5.5.31, 5.6.0-5.6.17, or 7.0.0-7.0.2, or is Fedora 22/Oracle Linux 7 with the vulnerable PCRE version present and processes regex patterns with lookbehind combined with recursive subpatterns.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.5.325.6.187.0.3
Upgrade PCRE library to version 8.38 or later across all affected systems. Identify and recompile any applications that link against the PCRE library to ensure they use the patched version.
PCRE 8.38+ or PHP 5.5.32+/5.6.18+/7.0.3+ (depending on which product uses the vulnerable PCRE)
- If using PCRE directly, upgrade PCRE to version 8.38 or later
- For PHP 5.5.x: upgrade to PHP 5.5.32 or later which includes fixed PCRE
- For PHP 5.6.x: upgrade to PHP 5.6.18 or later which includes fixed PCRE
- For PHP 7.0.x: upgrade to PHP 7.0.3 or later which includes fixed PCRE
- For Fedora 22 systems: apply available system updates or upgrade to a newer Fedora version
- For RHEL/CentOS Linux 7: apply vendor security updates via yum update
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Fedora
Scoped from the published advisory
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,544.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-8386 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-8386 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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