7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
0.004 Low
EPSS
Percentile
73.8%
An integer overflow in MetaDataBuilder.checkSize
allows for HTTP/2 HPACK header values to
exceed their size limit.
In MetaDataBuilder.java
, the following code determines if a header name or value
exceeds the size limit, and throws an exception if the limit is exceeded:
291 public void checkSize(int length, boolean huffman) throws SessionException
292 {
293 // Apply a huffman fudge factor
294 if (huffman)
295 length = (length * 4) / 3;
296 if ((_size + length) > _maxSize)
297 throw new HpackException.SessionException("Header too large %d > %d",
_size + length, _maxSize);
298 }
However, when length is very large and huffman is true, the multiplication by 4 in line 295
will overflow, and length will become negative. (_size+length) will now be negative, and
the check on line 296 will not be triggered.
Furthermore, MetaDataBuilder.checkSize
allows for user-entered HPACK header value sizes to be
negative, potentially leading to a very large buffer allocation later on when the
user-entered size is multiplied by 2.
In MetaDataBuilder.java
, the following code determines if a header name or value
exceeds the size limit, and throws an exception if the limit is exceeded:
public void checkSize(int length, boolean huffman) throws SessionException
{
// Apply a huffman fudge factor
if (huffman)
length = (length * 4) / 3;
if ((_size + length) > _maxSize)
throw new HpackException.SessionException("Header too large %d > %d", _size
+ length, _maxSize);
}
However, no exception is thrown in the case of a negative size.
Later, in Huffman.decode
, the user-entered length is multiplied by 2 before allocating a buffer:
public static String decode(ByteBuffer buffer, int length) throws
HpackException.CompressionException
{
Utf8StringBuilder utf8 = new Utf8StringBuilder(length * 2);
// ...
This means that if a user provides a negative length value (or, more precisely, a length
value which, when multiplied by the 4/3 fudge factor, is negative), and this length value is a
very large positive number when multiplied by 2, then the user can cause a very large
buffer to be allocated on the server.
An attacker repeatedly sends HTTP messages with the HPACK header 0x00ffffffffff02.
Each time this header is decoded:
HpackDecode.decode
will determine that a Huffman-coded value of lengthMetaDataBuilder.checkSize
will approve this length.Depending on the timing of garbage collection, the number of threads, and the amount of
memory available on the server, this may cause the server to run out of memory.
An attacker repeatedly sends HTTP messages with the HPACK header 0x00ff8080ffff0b. Each
time this header is decoded:
Depending on the timing of garbage collection, the number of threads, and the amount of
memory available on the server, this may cause the server to run out of memory.
Users of HTTP/2 can be impacted by a remote denial of service attack.
Fixed in Jetty 10.0.16 and Jetty 11.0.16
Fixed in Jetty 9.4.53
Jetty 12.x is unaffected.
No workarounds possible, only patched versions of Jetty.
www.openwall.com/lists/oss-security/2023/10/18/4
github.com/advisories/GHSA-wgh7-54f2-x98r
github.com/eclipse/jetty.project/pull/9634
github.com/eclipse/jetty.project/releases/tag/jetty-10.0.16
github.com/eclipse/jetty.project/releases/tag/jetty-11.0.16
github.com/eclipse/jetty.project/releases/tag/jetty-9.4.53.v20231009
github.com/eclipse/jetty.project/security/advisories/GHSA-wgh7-54f2-x98r
github.com/jetty/jetty.project/security/advisories/GHSA-wgh7-54f2-x98r
lists.debian.org/debian-lts-announce/2023/10/msg00045.html
nvd.nist.gov/vuln/detail/CVE-2023-36478
security.netapp.com/advisory/ntap-20231116-0011
security.netapp.com/advisory/ntap-20240621-0006
www.debian.org/security/2023/dsa-5540