CVE-2013-4852: Integer overflow in PuTTY 0.62 and earlier, WinSCP before 5.1.6, and other products that use PuTTY allows remo

Q: How do I fix CVE-2013-4852?

winscp: upgrade to newer than 5.1.5; debian linux: mitigate or apply the listed mitigation; opensuse: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2013-4852 being exploited?

CVE-2013-4852 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2013-4852 affect?

CVE-2013-4852 affects winscp, debian linux, opensuse. Severity is medium (CVSS 6.8). Integer overflow in PuTTY 0.62 and earlier, WinSCP before 5.1.6, and other products that use PuTTY allows remote SSH servers to cause a denial of service (crash) and possibly execute arbitrary code in certain applications that use PuTTY via

Q: How urgent is CVE-2013-4852?

Priority 51/100. On your watchlist

This month

MEDIUM 6.8WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2013-4852 is a medium-severity flaw (CVSS 6.8) affecting winscp, debian linux, opensuse. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in PuTTY 0.62 and earlier, WinSCP before 5.1.6, and other products that use PuTTY allows remote SSH servers to cause a denial of service (crash) and possibly execute arbitrary code in certain applications that use PuTTY via a negative size value in an RSA key signature during the SSH handshake, which triggers a heap-based buffer overflow.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.8 (Medium)
EPSS exploit chance	3.4% (top 11%)
CISA exploited list	No
Weakness	CWE-189
Published	2013-08-19
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: debian · opensuse · putty · simon tatham · winscp

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2013-08-19 23:55 UTCPublished CVE record published
2026-06-16 23:58 UTCUpdated Record last modified

winscp winscp UPGRADE

Affected: <= 5.1.5 · 3.7.6 · 3.8.2 · 3.8_beta · 4.0.4 · 4.0.5 · 4.2.6 · 4.2.7

Fixed in: newer than 5.1.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy winscp || rpm -q winscp || winscp --version

2. UPGRADE to newer than 5.1.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade winscp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade winscp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 6.0 · 7.0 · 7.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse opensuse MITIGATE

Affected: 12.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

putty putty DOWNGRADE

Affected: 0.45 · 0.46 · 0.47 · 0.48 · 0.49 · 0.50 · 0.51 · 0.52

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.45

1. Check installed version

apt-cache policy putty || rpm -q putty || putty --version

2. No fixed release: DOWNGRADE to a release before 0.45 (Debian / Ubuntu)

apt-cache madison putty sudo apt install putty=<VERSION_BEFORE_0.45> sudo apt-mark hold putty

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list putty sudo dnf downgrade putty-<VERSION_BEFORE_0.45> sudo dnf versionlock add putty

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

simon tatham putty UPGRADE

Affected: <= 0.62 · 0.53

Fixed in: newer than 0.62

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy putty || rpm -q putty || putty --version

2. UPGRADE to newer than 0.62 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade putty

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade putty

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2013-4852?

winscp: upgrade to newer than 5.1.5; debian linux: mitigate or apply the listed mitigation; opensuse: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2013-4852 being exploited?

CVE-2013-4852 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2013-4852 affect?

CVE-2013-4852 affects winscp, debian linux, opensuse. Severity is medium (CVSS 6.8). Integer overflow in PuTTY 0.62 and earlier, WinSCP before 5.1.6, and other products that use PuTTY allows remote SSH servers to cause a denial of service (crash) and possibly execute arbitrary code in certain applications that use PuTTY via

How urgent is CVE-2013-4852?

Priority 51/100. On your watchlist

Software pages

Debian vulnerabilities · PuTTY vulnerabilities

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References

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