CVE-2020-1917

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
—
EPSS
69.3%
KEV
Not listed

Published

March 10, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Jun 17, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

Security Update | HHVM

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

commit 08193b7f0cd3 (facebook/hhvm)

Fix landed in facebook/hhvm commit 08193b7f0cd3 — awaiting tagged release

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

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 22:36 UTCEG score recompute
  2. 2026-07-22 14:05 UTCEPSS rescore
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  38. 2026-06-12 23:10 UTCEPSS rescore
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  67. 2026-05-26 19:58 UTCEG score recompute
  68. 2026-05-26 19:58 UTCGHSA enrichment
  69. 2026-05-26 13:42 UTCEPSS rescore
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  71. 2026-05-26 07:17 UTCEPSS rescore
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  73. 2026-05-24 22:12 UTCOSV refresh

Frequently asked(5)

What is CVE-2020-1917?
CVE-2020-1917 is a critical vulnerability published on March 10, 2021. xbufformatconverter, used as part of exifreaddata, 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…
When was CVE-2020-1917 disclosed?
CVE-2020-1917 was first published in the National Vulnerability Database on March 10, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-1917 actively exploited?
CVE-2020-1917 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 69.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-1917?
CVE-2020-1917 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-1917?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-1917, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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