CVE-2015-6806 — screen: Stack overflow due to deep recursion causing process freeze

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MEDIUM

screen: Stack overflow due to deep recursion causing process freeze

Published Sep 28, 2015

5.0

MEDIUM

CVSS 2.0

EPSS 4.15%

Description

The MScrollV function in ansi.c in GNU screen 4.3.1 and earlier does not properly limit recursion, which allows remote attackers to cause a denial of service (stack consumption) via an escape sequence with a large repeat count value.

Affected products

Red Hat Enterprise Linux 5

screen

Will not fix
Red Hat Enterprise Linux 6

screen

Will not fix
Red Hat Enterprise Linux 7

screen

Will not fix

Product	Package	State	Advisory
Red Hat Enterprise Linux 5	screen	Will not fix	n/a
Red Hat Enterprise Linux 6	screen	Will not fix	n/a
Red Hat Enterprise Linux 7	screen	Will not fix	n/a

Remediation

No remediation recorded yet.

Metrics

4.15% 0.04148

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.

EPSS probability 0.04148

Score over time

2022–2026

EPSS v2
EPSS v3
EPSS v4
EPSS v5

Percentile over time

EPSS v2
EPSS v3
EPSS v4
EPSS v5

Table of values (12 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 1, 2026	4.15% (0.04148)	90.53th	v5 (v2026.06.15)
Jun 15, 2026	4.15% (0.04148)	89.51th	v5 (v2026.06.15)
Mar 30, 2025	0.95% (0.00952)	74.32th	v4 (v2025.03.14)
Mar 29, 2025	2.07% (0.02072)	73.27th	v4 (v2025.03.14)
Mar 17, 2025	0.95% (0.00952)	74.80th	v4 (v2025.03.14)
Dec 17, 2024	13.73% (0.13728)	95.61th	v3 (v2023.03.01)
Mar 10, 2023	6.12% (0.06120)	92.38th	v3 (v2023.03.01)
Mar 7, 2023	6.72% (0.06721)	92.70th	v3 (v2023.03.01)
Mar 6, 2023	1.41% (0.01408)	72.89th	v2 (v2022.01.01)
Mar 2, 2023	1.41% (0.01408)	72.88th	v2 (v2022.01.01)
Apr 1, 2022	1.41% (0.01408)	70.87th	v2 (v2022.01.01)
Feb 4, 2022	1.41% (0.01408)	49.94th	v2 (v2022.01.01)

Weaknesses (2)

CWE-119

Buffer Overflow

CWE-121

References (12)

http://git.savannah.gnu.org/cgit/screen.git/commit/?id=b7484c224738247b510ed0d268cd577076958f1b
x_refsource_CONFIRM
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00001.html
vendor-advisoryx_refsource_SUSE
http://www.debian.org/security/2015/dsa-3352
vendor-advisoryx_refsource_DEBIAN
http://www.openwall.com/lists/oss-security/2015/09/01/1
mailing-listx_refsource_MLIST
http://www.openwall.com/lists/oss-security/2015/09/03/11
mailing-listx_refsource_MLISTExploit
http://www.openwall.com/lists/oss-security/2015/09/03/4
mailing-listx_refsource_MLIST
https://access.redhat.com/security/cve/CVE-2015-6806
Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1258802
Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2015-6806
https://savannah.gnu.org/bugs/?45713
x_refsource_CONFIRMExploitVendor Advisory
https://usn.ubuntu.com/3996-1/
vendor-advisoryx_refsource_UBUNTU
https://www.cve.org/CVERecord?id=CVE-2015-6806

Link	Providers	Tags
http://git.savannah.gnu.org/cgit/screen.git/commit/?id=b7484c224738247b510ed0d268cd577076958f1b		x_refsource_CONFIRM
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00001.html		vendor-advisoryx_refsource_SUSE
http://www.debian.org/security/2015/dsa-3352		vendor-advisoryx_refsource_DEBIAN
http://www.openwall.com/lists/oss-security/2015/09/01/1		mailing-listx_refsource_MLIST
http://www.openwall.com/lists/oss-security/2015/09/03/11		mailing-listx_refsource_MLISTExploit
http://www.openwall.com/lists/oss-security/2015/09/03/4		mailing-listx_refsource_MLIST
https://access.redhat.com/security/cve/CVE-2015-6806		Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1258802		Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2015-6806
https://savannah.gnu.org/bugs/?45713		x_refsource_CONFIRMExploitVendor Advisory
https://usn.ubuntu.com/3996-1/		vendor-advisoryx_refsource_UBUNTU
https://www.cve.org/CVERecord?id=CVE-2015-6806