HOME VULNERABILITIESCVE-2020-1917

CRITICAL

CVE-2020-1917

CWE-122Published: March 10, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

xbuf_format_converter, used as part of exif_read_data, was appending a terminating null character to the generated string, but was not using its standard append char function. As a result, if the buffer was full, it would result in an out-of-bounds write. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.

Technical Analysis

CVE-2020-1917 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

facebook1 product(s)

hhvm

Source: NVD CPE · 6 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca

PATCHhttps://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca

ADVISORYhttps://hhvm.com/blog/2021/02/25/security-update.html

ADVISORYhttps://hhvm.com/blog/2021/02/25/security-update.html

All References (4)

→

https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44caPatch · Third Party Advisory

→

https://hhvm.com/blog/2021/02/25/security-update.htmlRelease Notes · Vendor Advisory

→

https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44caPatch · Third Party Advisory

→

https://hhvm.com/blog/2021/02/25/security-update.htmlRelease Notes · Vendor Advisory

Quick Facts

CVE IDCVE-2020-1917

CVSS Score9.8 / 10

SeverityCRITICAL

WeaknessCWE-122

CISA KEVNo

Affected1 vendor(s)

PublishedMar 10, 2021

Related CVEs (CWE-122)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2020-1917 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.COM. CVE data is provided under the NVD usage policy.

← All Vulnerabilities·Search for CVE-2020-1917·NVD