How severe is CVE-2013-4207?

CVE-2013-4207 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2013-4207 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2013-4207?

CVE-2013-4207 primarily affects Putty. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2013-4207?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2013-4207 published?

CVE-2013-4207 was published on 2013-08-19 and last updated on 2026-06-16.

CVE-2013-4207

CVE-2013-4207 is a medium-severity vulnerability in Putty with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Putty
Published: 2013-08-19
Last modified: 2026-06-16

Description

Buffer overflow in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) via an invalid DSA signature that is not properly handled during computation of a modular inverse and triggers the overflow during a division by zero by the bignum functionality, a different vulnerability than CVE-2013-4206.

Frequently asked questions

What is CVE-2013-4207?: Buffer overflow in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) via an invalid DSA signature that is not properly handled during computation of a modular inverse and triggers the overflow during a division by zero by the bignum functionality, a different vulnerability than CVE-2013-4206.
How severe is CVE-2013-4207?: CVE-2013-4207 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2013-4207 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2013-4207?: CVE-2013-4207 primarily affects Putty. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2013-4207?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2013-4207 published?: CVE-2013-4207 was published on 2013-08-19 and last updated on 2026-06-16.

References

Affected products (20)

cpe:2.3:a:putty:putty:0.45:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.46:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.47:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.48:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.49:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.50:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.51:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.52:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.53b:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.54:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.55:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.56:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.57:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.58:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.59:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.60:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:0.61:*:*:*:*:*:*:*
cpe:2.3:a:putty:putty:2010-06-01:r8967:*:*:development_snapshot:*:*:*
cpe:2.3:a:simon_tatham:putty:*:*:*:*:*:*:*:*
cpe:2.3:a:simon_tatham:putty:0.53:*:*:*:*:*:*:*

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