CVE-2021-20307Network attack vector

Memory read and write via format-string prefix

Published Apr 5, 2021 · Updated Aug 3, 2024

Format string injection in libpano13 2.9.20_rc2 and earlier allows attackers to read or write process memory via a filename prefix. panoFileOutputNamesCreate() accepts percentage signs in an externally controlled filename-prefix string, causing formatting directives to be interpreted instead of treated as filename text. An application must pass an attacker-controlled prefix into the affected function; exploitation exposes or modifies that application's process memory, while malformed prefixes can crash it.

CVSS severity9.8
Critical
EPSS probability1.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format string injection in libpano13 2.9.20_rc2 and earlier allows attackers to read or write process memory via a filename prefix. panoFileOutputNamesCreate() accepts percentage signs in an externally controlled filename-prefix string, causing formatting directives to be interpreted instead of treated as filename text. An application must pass an attacker-controlled prefix into the affected function; exploitation exposes or modifies that application's process memory, while malformed prefixes can crash it.

The record

CVE
CVE-2021-20307
Published
Apr 5, 2021
Updated
Aug 3, 2024
Vendor
Panorama Tools
Product
libpano13
Classifications
CWE-134, CAPEC-135
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=libpano13 2.9.20_rc3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Panorama Tools · libpano13version=libpano13 2.9.20_rc3

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String
CAPEC-135Format String Injection

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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