CVE-2026-54736
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 · uneditedPhalcon is a high-performance, full-stack PHP framework. Prior to 5.14.1, Phalcon\Encryption\Crypt::decrypt compares the attacker-supplied HMAC tag against the freshly computed HMAC using PHP/Zephir identity comparison, which lowers to a byte-wise comparison that returns early on the first differing byte. This observable timing discrepancy can allow an attacker to recover a valid tag byte-by-byte and attach it to a chosen IV and ciphertext so that decrypt() accepts tampered encrypted content as authentic. This issue is fixed in version 5.14.1.
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 confidencePhalcon's Crypt::decrypt uses identity comparison (==) to verify HMAC tags, which returns early on the first differing byte. This timing leakage allows attackers to perform timing attacks, recovering the HMAC byte-by-byte and forging valid authentication tags for tampered IV/ciphertext.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- High
- Privileges
- None
- Authentication
- X
- User interaction
- None
- Scope
- X
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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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Verify Phalcon extension is installedRun `php -m | grep -i phalcon` or check phpinfo() output for the phalcon extensionAffected if Phalcon extension is not loaded in PHP
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Determine installed Phalcon versionRun `phalcon version` command, or inspect the Phalcon version from phpinfo() output, or check the extension file version metadataAffected if Version is below 5.14.1 (the fixed release)
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Identify Crypt::decrypt usage in application codeSearch PHP source files for calls to \Phalcon\Crypt::decrypt method or $crypt->decrypt()Affected if Application code calls the decrypt method on Phalcon Crypt objects
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Confirm HMAC authentication is being verifiedReview the Crypt configuration and verify that HMAC-based encryption is in use (check for cipher setup and key usage in the decrypt flow)Affected if The Crypt::decrypt method is performing HMAC tag verification on decrypted data
User is affected if running Phalcon version below 5.14.1 and the application uses Phalcon Crypt component for decryption with HMAC authentication tags.
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 · scopedUpgrade Phalcon to version 5.14.1 or later, which implements constant-time HMAC comparison.
5.14.1
- Update the Phalcon framework dependency to version 5.14.1 or later using your package manager (e.g., composer update phalcon/cphalcon)
- Verify the update was successful by checking the installed version matches or exceeds 5.14.1
- Test the application's encrypt/decrypt functionality to ensure it works correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,840.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-54736 — 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-2026-54736 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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