HOMEVULNERABILITIESCVE-2021-23803
CRITICAL

CVE-2021-23803

CWE-863Published: December 17, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

This affects the package latte/latte before 2.10.6. There is a way to bypass allowFunctions that will affect the security of the application. When the template is set to allow/disallow the use of certain functions, adding control characters (x00-x08) after the function will bypass these restrictions.

NVD Source

Technical Analysis

CVE-2021-23803 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

nette1 product(s)
latte
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/nette/latte/commit/227c86eda9a8a6d060ea8501923e768b6d992210
PATCHhttps://github.com/nette/latte/issues/279
PATCHhttps://snyk.io/vuln/SNYK-PHP-LATTELATTE-1932226
PATCHhttps://github.com/nette/latte/commit/227c86eda9a8a6d060ea8501923e768b6d992210
PATCHhttps://github.com/nette/latte/issues/279
PATCHhttps://snyk.io/vuln/SNYK-PHP-LATTELATTE-1932226

All References (6)

→
https://github.com/nette/latte/commit/227c86eda9a8a6d060ea8501923e768b6d992210Patch · Third Party Advisory
→
https://github.com/nette/latte/issues/279Exploit · Issue Tracking · Patch · Third Party Advisory
→
https://snyk.io/vuln/SNYK-PHP-LATTELATTE-1932226Exploit · Patch · Third Party Advisory
→
https://github.com/nette/latte/commit/227c86eda9a8a6d060ea8501923e768b6d992210Patch · Third Party Advisory
→
https://github.com/nette/latte/issues/279Exploit · Issue Tracking · Patch · Third Party Advisory
→
https://snyk.io/vuln/SNYK-PHP-LATTELATTE-1932226Exploit · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-23803
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-863
CISA KEVNo
Affected1 vendor(s)
PublishedDec 17, 2021

Related CVEs (CWE-863)

CVE-2018-18815
10.0
CVE-2021-38503
10.0
CVE-2026-48303
10.0
CVE-2026-48321
10.0
CVE-2023-4617
10.0
CVE-2026-44330
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-23803 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2021-23803·NVD