FedoraOperating system · Fedoraproject
CVE-2015-8853
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 · uneditedThe (1) S_reghop3, (2) S_reghop4, and (3) S_reghopmaybe3 functions in regexec.c in Perl before 5.24.0 allow context-dependent attackers to cause a denial of service (infinite loop) via crafted utf-8 data, as demonstrated by "a\x80."
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 confidenceA denial of service vulnerability exists in Perl versions before 5.24.0 in the regexec.c file. The S_reghop3, S_reghop4, and S_reghopmaybe3 functions that handle UTF-8 data can be triggered into an infinite loop when processing specially crafted UTF-8 input, as demonstrated by the string 'a\x80'.
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
PerlApplication
<= 5.23.9CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Determine installed Perl versionRun 'perl -v' or 'perl --version' to display version informationAffected if Version displayed is 5.23.9 or earlier, or any version less than 5.24.0
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Confirm version number preciselyRun 'perl -e "print $^V"' to output the version string in V format (e.g., v5.23.8)Affected if The version string starts with v5.23.x or lower (v5.22.x, v5.21.x, etc.)
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Identify if UTF-8 data is processed through regexReview application code or scripts to determine if Perl's regular expression engine handles UTF-8 encoded strings (especially strings containing bytes 0x80-0xFF)Affected if Code processes UTF-8 strings through regex operations such as m//, s///, or split with UTF-8 data containing malformed sequences
You are affected if your installed Perl version is 5.23.9 or earlier (below 5.24.0) and your code processes UTF-8 data through Perl's regex engine, as the infinite loop can be triggered by crafted UTF-8 input like the byte sequence \x80 in a string.
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.
From vendor dataUpgrade Perl to version 5.24.0 or later to receive the patch for this vulnerability. If immediate upgrading is not feasible, consider input validation to reject malformed UTF-8 sequences before they reach the regex engine.
Fix this in Fedora
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,144.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-8853 — 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-2015-8853 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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