CVE-2021-39559 json
An issue was discovered in swftools through 20200710.
published 2021-09-20 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-25916
- cvss
- 5.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 50%
- public exploits
- 0
- none known
Summary
An issue was discovered in swftools through 20200710. A NULL pointer dereference exists in the function GString::~GString() located in GString.cc. It allows an attacker to cause Denial of Service.
Exploit prediction
0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/matthiaskramm/swftools/issues/101 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:N/A:P |
Classification
- Weakness
-
- CWE-476 NULL Pointer Dereference
References
-
github.com
/matthiaskramm/swftools/issues/101
exploit, issue-tracking, third-party-advisory
Sources
- CVE List CVE-2021-39559
- NVD CVE-2021-39559
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.