CVE-2020-35573: srs2.c in PostSRSd before 1.10 allows remote attackers to cause a denial of service (CPU consumption) via a lo

Q: How do I fix CVE-2020-35573?

postsrsd: upgrade to 1.10; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-35573 being exploited?

CVE-2020-35573 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-2020-35573 affect?

CVE-2020-35573 affects postsrsd, debian linux. Severity is high (CVSS 7.5). srs2.c in PostSRSd before 1.10 allows remote attackers to cause a denial of service (CPU consumption) via a long timestamp tag in an SRS address.

Q: How urgent is CVE-2020-35573?

Priority 58/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2020-35573 is a high-severity flaw (CVSS 7.5) affecting postsrsd, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

srs2.c in PostSRSd before 1.10 allows remote attackers to cause a denial of service (CPU consumption) via a long timestamp tag in an SRS address.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.7% (top 14%)
CISA exploited list	No
Weakness	CWE-834
Published	2020-12-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · postsrsd project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-12-20 05:15 UTCPublished CVE record published
2026-06-17 03:13 UTCUpdated Record last modified

postsrsd project postsrsd UPGRADE

Affected: < 1.10

Fixed in: 1.10

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.10 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade postsrsd

Note

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

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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.

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-2020-35573?

postsrsd: upgrade to 1.10; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-35573 being exploited?

CVE-2020-35573 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-2020-35573 affect?

CVE-2020-35573 affects postsrsd, debian linux. Severity is high (CVSS 7.5). srs2.c in PostSRSd before 1.10 allows remote attackers to cause a denial of service (CPU consumption) via a long timestamp tag in an SRS address.

How urgent is CVE-2020-35573?

Priority 58/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2021-35525 MEDIUM 5.3 UPGRADE PostSRSd before 1.11 allows a denial of service (subprocess hang) if Postfix sends certain long data fields su

References

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